The Water FAQ
Table of Contents
- Water Basics
- Hard Water
- What is hard
water?
- What are
hardness minerals?
- How do you
measure hardness?
- Why should
hard water concern me?
- Who will
test my water for hardness?
- My water
is hard; now what?
- Which water
conditioning company should I call?
- What should
I look for in a water conditioner?
- I have a
water conditioner, now my water feels "slimy"!
- Water that
Smells
- My water
stinks! What can I do?
- OK, it's
my raw water that smells -- now what?
- Minor,
musty smell
- Strong,
rotten-egg smell
- Strong,
musty smell
Solutions:
- Filters
- Feeders
- Aeration
- Water that
Stains
- I have red
stains in my sinks and other fixtures -- Help!!
Iron types:
- oxidized
- soluble
- colloidal
- bacterial
- organic-bound
- I have blue or green stains
on my fixtures -- Help!!
- copper
in your water supply
- copper
pipes & corrosive water
- Improving
your drinking water
- Filters
- Selective
Resins
- Deinonization
- Distillation
- Reverse
Osmosis
- What is the
best water for coffee?
- Water Testing
Information
- When Should
I Test?
- What Could
I Test For?
- An Easy
Way to Test
Water Basics
Water is generally classified
into two groups: Surface Water and Ground Water. Surface water
is just what the name implies; it is water found in a river,
lake or other surface impoundment. This water is usually not
very high in mineral content, and many times is called "soft
water" even though it usually is not. Surface water is exposed
to many different contaminants, such as animal wastes, pesticides,
insecticides, industrial wastes, algae and many other organic
materials. Even surface water found in a pristine mountain
stream possibly contains Giardia or Coliform Bacteria from
the feces of wild animals, and should be boiled or disinfected
by some means prior to drinking.
Ground Water is that which is trapped beneath the ground.
Rain that soaks into the ground, rivers that disappear beneath
the earth, melting snow are but a few of the sources that
recharge the supply of underground water. Because of the many
sources of recharge, ground water may contain any or all of
the contaminants found in surface water as well as the dissolved
minerals it picks up during it's long stay underground. Waters
that contains dissolved minerals, such as calcium and magnesium
above certain levels are considered "hard water" Because water
is considered a "solvent", ie, over time it can break down
the ionic bonds that hold most substances together, it tends
to dissolve and 'gather up' small amounts of whatever it comes
in contact with. For instance, in areas of the world where
rock such as limestone, gypsum, fluorspar, magnetite, pyrite
and magnesite are common, well water is usually very high
in calcium content, and therefore considered "hard".
Due to the different characteristics of these two types of
water, it is important that you know the source of your water
-- Surface or Ground. Of the 326 million cubic miles of water
on earth, only about 3% of it is fresh water; and 3/4 of that
is frozen. Only 1/2 of 1% of all water is underground; about
1/50th of 1% of all water is found in lakes and streams. The
average human is about 70% water. You can only survive 5 or
less days without water.
[ Back to Table
of Contents ]
Hard Water
What is hard water?
Hard water is the most common
problem found in the average home. Hard water is water that
contains dissolved hardness minerals above 1 GPG.
What are hardness minerals?
Calcium, manganese and magnesium
are the most common.
How do you Measure Hardness?
Parts per million or grains per
gallon are the most common. One part per million (PPM) is
just what it says: out of one million units, one unit. Grains,
or grains per gallon (GPG) is a weight measurement taken from
the Egyptians; one dry grain of wheat, or about 1/7000 of
a pound. It takes 17.1 PPM to equal 1 GPG.
Why Should Hard Water Concern
Me?
For many uses, it would not matter.
For instance, to put out fires, water your lawn, wash the
mud off the streets or float your boat, water would have to
be pretty hard to cause a problem. But for bathing, washing
dishes and clothes, shaving, washing your car and many other
uses of water, hard water is not as efficient or convenient
as "soft water." For instance:
- you use only 1/2 as much soap
cleaning with soft water.
- because hard water and soap
combine to form "soap scum" that can't be rinsed off, forming
a 'bathtub ring' on all surfaces and drys leaving unsightly
spots on your dishes.
- when hard water is heated,
the hardness minerals are re-crystallized to form hardness
scale. This scale can plug your pipes and hot water heater,
causing premature failure, necessitating costly replacement.
- the soap scum remains on your
skin even after rinsing, clogging the pores of your skin
and coating every hair on your body. This crud can serve
as a home for bacteria, causing diaper rash, minor skin
irritation and skin that continually itches.
- for many industrial uses,
the hardness minerals interfere with the process, causing
inferior product.
Who Will Test My Water for Hardness?
If you are connected to a municipal
supply, call the water Superintendent, or City Hall. They
can either provide the answer, or direct you to the proper
individual. Remember the conversion factor: it takes 17.1
PPM to equal 1 GPG. In other words, if your water has 171
PPM calcium in it, divide 171 by 17.1 to get the answer in
grains. This example would be 10 grains, or GPG.
If you are on a private supply, you could contact your county
extension agent: collect a sample in an approved container
and send to the city or state health department for testing:
find a testing lab (try the yellow pages): call a water conditioning
company. By the way, if you are on a private well, YOU, AND
YOU ALONE are responsible for the safety of the water you
and your family drink. You should test your supply for bacteria
at least once per year and other contaminants at least every
three years -- more under certain conditions.
My Water is Hard; Now What?
If your water tests over 3 GPG
hard, you should mechanically soften it. Softening water that
is less than 3 GPG, while it makes your shaving and bathing
more comfortable, is considered a luxury due to the fact that
the cost is more than your savings. Over 3 GPG, you will save
enough to pay for the cost and maintenance of a water conditioner.
As of this writing, the most economical way for you to soften
your household water is with an ion exchange water softener.
This unit uses sodium chloride (salt) to recharge man made
plastic like beads that exchange hardness minerals for sodium.
As the hard water passes through and around the plastic like
beads, the hardness minerals (ions) attach themselves to the
bead, dislodging the sodium ions. This process is called "ion
exchange". When the plastic bead, called Resin, has no sodium
ions left, it is exhausted, and can soften no more water.
The resin is recharged by flushing with salt water. The sodium
ions force the hardness ions off the resin beads; then the
excess sodium is rinsed away, and the resin is ready to start
the process all over again. This cycle can be repeated many,
many time before the resin loses it's ability to react to
these forces.
Which Water Conditioning Company
should I call?
As in any purchase, talk to your
friends and neighbors -- who do they use? Are they happy with
them? Check with the Better Business Bureau for complaints.
The BBB can't prevent shady business, but they can and do
keep a file of complaints filed by people who have had dealings
with them.
Ask at least two to come to your home to look at your plumbing
and then give you a quote on their equipment. Have them explain
all the features of the unit, as well as the warranty.
What Should I look for in a Water
Conditioner?
Make sure the unit has enough
resin to treat all the water you and your family will use.
As of this writing, the average usage per day, per person
(including children), for inside the house is 87 gallons.
You should also be shown two or three ways to initiate recharging
the unit.
The oldest way is by a timeclock, ie, your water usage is
calculated and the frequency of recharging programmed into
the timer. On the appointed day, at the appointed hour, the
unit recharges. If all went as calculated, ok. If you were
gone -- too bad -- you just wasted salt and water. If you
had extra company -- too bad -- you ran out of soft water.
You must pick a unit that will treat one days supply of water
and still have about 40% of the resin in the recharged state.
This will provide you with the most efficiency for salt and
regeneration water.
A second way to initiate recharge is by electronic sensing.
By electronically checking the resin, these units can determine
when the resin needs to be recharged -- this is a great help
when your water hardness changes, when you have extra company
or when you are gone for a few days. These 'sensor' units
can save you up to 42% of your salt and recharge water as
well as keep you in soft water when you have extra guests.
A third way to initiate recharge is by using a meter. These
units have a meter installed in the water line and simply
measure how many gallons of water you actually used. The unit
is set according to your water hardness, and will recharge
when the gallons used approach exhaustion of the resin bed,
saving you a high percentage of your recharge salt and water.
Many variations of these methods are on the market. Some use
computers to calculate in advance, when to recharge the unit;
some have two resin beds (tanks), and switch back and forth
between the two, keeping you in soft water all the time, at
the highest efficiency. These systems are most effective in
high-hardness waters, ie, over 10-12 GPG, and over 4 people
in the family. Low hardness water and smaller families do
not require the extra expense of these options.
I Have a Water Conditioner, Now
my Water Feels "Slimy"
When the hardness minerals are
removed, soap no longer forms a soap curd, or "bathtub ring"
on your skin, plugging your pores, clinging to every strand
of hair. You are now truly clean. That slick, slimy feeling
you feel is your natural body oils -- without the soap scum.
The old saying that you get "squeaky clean" is a myth; that
feeling was caused by the soap scum on your skin. By the way,
that soap scum provided an excellent place for bacteria to
hide and grow, causing numerous minor skin ailments.
[ Back to Table
of Contents ]
Water that Smells
My Water Stinks! What can I Do?
First, you must learn a little
about your nose: Once you smell some things, your sense of
smell is dulled for a short while, and you can't make accurate
judgments of smell. For instance, if I blindfold you, let
you smell gasoline, hand you a piece of onion to eat and tell
you it is an apple, you can't tell it's not because your nose
isn't working properly!! (Your sense of taste isn't working
either -- smell and taste are closely related and affect each
other!)
So, to correctly analyze your problem, you need to become
a detective. The best time to locate the smell is after you
have been away from home for a few hours -- this allows your
nose to become sensitive to "that smell" again. With your
'sensitized' nose, go to an outside spigot -- one that the
raw, untreated water flows from. Turn it on, let it run a
few minutes, then smell it. If it smells -- we found it. If
not, we must look further. (Many, many smells are not in the
raw water at all, they are introduced into the water inside
the house.) Go to a cold, treated water spigot inside the
house, turn it on and let it run a minute; then smell. If
this water smells, and the outside, untreated water didn't
-- you must have a device (cartridge filter, water softener,
etc.) in the water line that needs to be cleaned and sanitized.
If it is a cartridge, or 'string' filter, replace the element
and sanitize the housing. If you have a water conditioner
call the Company where you bought the unit for advise on how
to sanitize the unit. If you rent the unit, just call! You
can sanitize the unit by pouring Hydrogen Peroxide or Chlorine
Bleach in the brine well of the salt tank, and placing the
unit into regeneration. Check with the seller, or, if they
are no longer in business, any Professional Water Conditioning
Dealer for how much to put in your particular unit.
If the cold, treated water inside didn't smell, turn on the
hot water and let it run a few minutes -- does it smell? If
it does, chances are you have a sacrificial anode inside your
hot water heater that is "coming apart at the seams" and throwing
off a "rotten egg" odor. This obnoxious smell will drive you
right out of your shower! The only solution is to remove the
anode from the heater, voiding your warranty, or replace it
with a new one made with aluminum alloy. This anode is placed
in a (glass lined) hot water heater to seal up any cracks
in the glass lining and prevent corrosion of the heater tank.
You will find the anode on the top of the heater; remove the
tin cover and insulation -- look for what looks like a pipe
plug -- about 3/4 inch in size with a 1 1/16"fitting. Turn
off the heat source and the water; have someone hold the tank
to prevent it from turning, and unscrew the "plug". You will
find that the 'plug' has a 30 - 40 " long pipe (or what's
left of one) attached to it. Hopefully, most of the rod is
still attached -- just corroded. If so, replace the plug with
a real pipe plug and throw the anode away. If part of the
rod has corroded off, and fallen into the heater, you may
have to try to fish it out. Either way, before you plug the
hole, pour about 2 pints of chlorine bleach into the heater
first. This will kill the smell left in the heater. If, after
a week or so, the smell returns, you must fish out the rod
that is in the bottom of the tank. Good Luck!
OK, It's my Raw Water That Smells
-- Now What?
First, you must determine what
is causing the smell, and how strong it is.
Minor, musty smell
If it is a minor, or low-level
smell, you MIGHT be able to solve it with a small, point-of-use
carbon filter. You can place these types of filters on the
water line going to the cold water where you draw you drinking
water. Or, you might solve it with a whole-house filter on
your incoming water line to filter all of the water inside
your home.
Because carbon removes smells by ADsorbtion, ie, the smell
"sticks" or "adheres" to the carbon particles, you must be
careful not to exceed the manufactures recommended flow --
some filters even have a flow restriction built in them. If
you run water through them too fast, you will not remove the
smells. Whenever you place a carbon filter in your water line,
you must be sure to replace the element and sanitize the housing
on a regular basis. Carbon filters remove organics from water,
and the bacteria found in water like to eat organics -- the
carbon filter is a nice, dark place, just full of food for
them to grow and reproduce in. Regular and routine replacement
will help prevent any buildup of bacteria in the cartridge.
Strong, rotten-egg smell
Strong, rotten-egg odors in the
raw water is usually the result of the decomposition of decaying
underground organic deposits. As water is drawn to the surface,
hydrogen sulfide gas can be released to the atmosphere. In
strong concentrations, this gas is flammable and poisonous.
It rapidly tarnishes silver, turning it black. It is toxic
to aquarium fish in sufficient quantities. As little as 0.5
ppm hydrogen sulfide can be tasted in your drinking water.
Strong, musty smell
If you are unlucky enough to
have this problem, you should look for a company that has
local experience in dealing with this problem. There are three
basic ways to solve this problem for homeowners.
Filters
Installation of a whole house
filter loaded with a media that is specific for hydrogen
sulfide removal is successful many times. These types of
filters must be recharged with chlorine or potassium permanganate.
The removal capacities of these types of filters are usually
fairly low, and must be sized to contain enough media to
prevent premature exhaustion, and subsequent passage of
the smell to service. It is also typical that the amount
of hydrogen sulfide can fluctuate rapidly, causing great
difficulty in sizing the unit. In addition, potassium permanganate
is extremely "messy", and will leave stains that are very
difficult to remove.
Feeders
Feeder systems consist of a small
pump that injects small amounts of chlorine (usually) into
the incoming water. The water must then be held for a short
period of time to allow the hydrogen sulfide to precipitate
out of the water. This tank should be designed in such a
manner that the water that enters it will mix thoroughly
with the water in the tank, to assure complete reaction.
The water then should pass through a filter to remove both
the precipitated matter and the chlorine remaining in the
water. You should be aware, however, that whenever you mix
chlorine with organic materials (remember where hydrogen
sulfide come from!), the chances are very high that trihalomethanes
(possible cancer causing carginigns) will be formed. Also,
feeder maintenance is high, you should be prepared to "play"
with the unit frequently.
Aeration
Aeration consists of breaking
the incoming water into small droplets (spray) into the
air, drawing fresh air through that spray, collecting the
water into a storage tank, repressurize the water, passing
it through a particulate filter to catch any particles that
might be carried out of the storage tank. The air drawn
though the spray must be vented outside the house -- remember,
it is toxic and explosive. Although this system necessitates
another pump to repressurize your supply, you are not adding
any chemicals to your water, which makes it attractive.
This system is low maintenance and no chemicals to purchase.
Initial cost may be higher, however, and space requirements
may be greater.
[ Back to Table
of Contents ]
Water that Stains
I have Red Stains in my Sinks
and Other Fixtures -- Help!
Red stains are normally caused
by iron in the water. You must test to determine the amount
and the type of iron you have. Some types are: oxidized, soluble,
colloidal, bacteria or organic-bound. All are a problem! It
only takes 0.3 ppm to stain clothes, fixtures, etc.
Oxidized
This type of iron is usually
found in a surface water supply. This is water that contains
red particles when first drawn from the tap. The easiest way
to remove this type of iron is by a fine mechanical filter.
A cartridge type filter is usually not a good solution, due
to the rapid plugging of the element. Another method or removal
is by feeding a chemical into the water to cause the little
particles of iron to clump together, and then fall to the
bottom of a holding tank, where they can be flushed away.
Soluable
Soluble iron is called "clear
water" iron. After being drawn form the well and contacting
the air, the iron oxidizes, or "rusts", forming reddish brown
particles in the water. Depending on the amount of iron in
the water, you may solve this problem with a water conditioner,
or a combination of softener and filter. You may use an iron
filter that recharges with chlorine or potassium permanganate,
or feed chemicals to oxidize the iron and then filter it with
a mechanical filter. You can sometimes hide the effects of
soluble iron by adding chemicals that, in effect, coat the
iron in the water and prevent it from reaching oxygen and
oxidizing.
Colloidal
Colloidal iron is very small
particles of oxidized iron suspended in the water. They are
usually bound together with other substances. They resist
agglomeration, ie, the combining together of like substances
forming larger, heavier, more filterable ones, due to the
static electrical charge they carry. This iron looks more
like a color than particles when held up in a clear glass,
as they are so small. Treatment is usually one of two: Feed
chlorine to oxidize the organic away from the iron, thus allowing
agglomeration to occur, or, feeding polymers that attract
the static charge on the particles, forming larger clumps
of matter that is filterable.
Bacterial
Iron bacteria are living organisms
that feed on the iron found in the water, pipes, fittings,
etc. They build slime all along the water flow path. Occasionally,
the slimy growths break free, causing extremely discolored
water. If a large slug breaks loose, it can pass through to
the point of use, plugging fixtures. These types of bacteria
are becoming more common throughout the United States. If
you suspect bacteria iron, look for a reddish or green slime
buildup in your toilet flush tank. To confirm your suspicions,
gather a sample of this slime and take it to your local health
department, or water department for observation under the
microscope. This type of iron problem is very hard to eliminate.
You must kill the bacteria, usually by chlorination. You must
use high amounts of chlorine throughout your plumbing system
to kill all organisms. You may find it necessary to feed chlorine
continuously to prevent regrowth. A filter alone will not
solve this problem.
Organic bound
When iron combines with tannins
and other organics, complexes are formed that cannot be removed
by ion exchange or oxidizing filters. This iron may be mistaken
for colloidal iron. Test for tannins; if they are present,
it is most likely combined with the iron. Low level amounts
of this pest can be removed by use of a carbon filter, which
absorbs the complex. You must replace the carbon bed when
it becomes saturated. Higher amounts require feeding chlorine
to oxidize the organics to break apart from the iron and cause
both to precipitate into a filterable particle.
I Have Blue or Green Stains on
my Fixtures -- Help!
You either have copper in your
water supply, or you have copper pipes and corrosive water.
Test for copper in your water. Test the pH, total dissolved
solids content and the oxygen content of your water.
Copper
Copper can be removed by ion
exchange, ie, a water softener. The removal rate is about
the same as it is for iron.
Copper pipes and corrosive water
If your pH is from 5 to 7, you
may raise it by passing the water through a sacrificial media.
By sacrificing calcium carbonate into the water, the corrosively
will be reduced. If the pH is below 5, you will need to feed
chemicals into the water.
If the corrosively is caused by excess oxygen, the hot water
will be much more corrosive than the cold. Treatment is by
feeding polyphosphate or silicates to coat and protect the
plumbing, or to aeriate the water to release the excess oxygen.
[ Back to Table
of Contents ]
Improving your Drinking Water
Filters; what can they do?
There are many types of filters
available in the market place today. I will try to group them
by the method they use to filter water. Almost everyone has
seen the ads for the filter that fits on the end of your kitchen
sink or bathroom spigot. These filters usually use two basic
types of filtration: a filter 'pad' catches the large (usually
over 25 micron in size) particles or 'chunks' , and a small
amount of carbon to adsorb organics and/or chlorine. The main
problem here is the flow rates at which they are expected
to work at. The consumer expects to turn the tap on as normal
and draw "filtered" water. To remove free chlorine, for instance,
standard engineering practices set the maximum flow rate at
10 gallons per minute per square foot (144 square inches)
of surface area of the carbon, *if* you are using a standard
30" bed depth. To remove chloramines or organics, the maximum
flow rate is set at 5 gallons per minute per square foot of
surface area. If your spigot will provide a flow of 1.5 gallons
per minute, what size filter do you need hanging on the end
of that spigot to insure that the chlorine and organics will
not be swept past through the filter, into your glass? If
you purchase this type of filter, make sure it has a way of
limiting the rate at which water passes through it.
Next comes the cartridge type filter. Most common are the
10 1/2 or 20 inch long filters. This type filter will usually
have a removable housing, into which different types of "elements"
can be placed. A sediment filter cartridge element can be
manufactured to remove certain size particles and larger.
Most elements for home use will indicate 30 or 50 micron and
larger removal. More expensive elements, usually for industrial
use, may indicate a particle size (in microns) and add the
words "Absolute" after it. No, it isn't Vodka, it simply means
that if it says 5 micron absolute, it means it! Very few particles
larger than 5 microns will pass through the filter. The regular
filter may say 25 microns, meaning that *most* of the particles
25 microns and larger will be caught by the filter. Remember,
there filters actually get better, or more effective, as they
are used. The 'junk' in the water collects on the surface
of the filter and becomes a part of the filter as well. As
it builds up, progressively smaller and smaller particles
are trapped, and the flow rate through the filter slowly diminishes.
This slowing of the flow rate can be a source of problems
to water using appliances in your home. If you use such a
filter, regular changing of the filter element is very important.
Elements for these filters can also be carbon (block or granular,
or powdered), can be manufactured for use in hot water, can
be ceramic, pleated as well as many other configurations.
Some manufacturers are mixing a small amount of silver into
the carbon to help prevent any bacteria growth in them. This
has yet to be a proven methodology. In fact, make sure that
such a filter doesn't give off more silver than is allowed,
if not rinsed thoroughly prior to use, especially after a
prolonged period of non-use. Remember, all filters, carbon
especially, trap organics that bacteria feed on, and as the
water sits without moving, they can multiply rapidly. Always
change the elements on a regular, frequent basis.
Selective Resins
A relative
newcomer to the market, some small filters now contain resins
that only remove specific things from the water, such as Nitrates,
Fluoride or Lead. Technology is rapidly changing in this area; If you have a need
for such a device, you should ask for supporting test results
from an independent testing lab to verify that the unit will
perform as advertised. Many states now have legislation that
requires such data be provided to you prior to purchase.
Deionization
Used mainly in labs, manufacturing
processes, or for serious aquarium owners, DI filters are
actually more complex than a filter. True filters, unlike
the selective resin and DI units, work on a mechanical basis:
they just 'catch' the particles that are too large to fit
through the spaces between the filter media. (Well, I fibbed
a little; but who wants to know about the Van Der Waals or
Coulomb forces?) DI works by ion exchange, just like a water
softener. Just as a water softener exchanges sodium for hardness
minerals, a DI unit will have two types of resin in it: Cation
and Anion. Basically, the Cation resin (like in a water softener)
removes the ions with a positive charge, while the Anion resin
removes those ions with a negative charge. Instead of using
salt as a regenerant, acid and caustic are used. Some small
DI cartridges are sold as "throw-aways", others can be returned
for regeneration and reuse. These small units can treat only
small amounts of raw, city water. Usually, it is much more
economical to pretreat the water feeding a DI system with
reverse osmosis water.
Distillation
One of the oldest methods for
cleaning water is distillation. Simply put, you boil water,
catch the steam, and condense it back into water. Theory is,
the minerals stay behind in the boiling chamber, and only
*pure* water ends up in your container. In the real world,
most of those things do happen; but if you do not perform
preventative maintenance on your still, you can get very poor
results. Distillation will kill bacteria, viruses, cysts as
well as remove heavy metals, organics, radionuclides, inorganics
and particulates if properly maintained. One thing you must
watch out for is VOC's (volatile organic chemicals). These
chemicals have a lower boiling point than water (like benzene),
and can vaporize and mix with the steam, carrying over into
the product water. Some stills today have a volitle gas vent
-- a small hole at the top of the condensing coil that allows
the venting of such substances. Many distillers have a carbon
filter to "polish" the product water before use and to remove
any VOC's that may carry over. The energy used to treat a
gallon of water is usually about 3,000 watts, or about 25
cents per gallon (average) in the US. This treatment method
requires that you 'plan ahead' and make and store water for
use, which makes it somewhat less appealing. The more elaborate
units will make and store water automatically, but raise the
initial investment and maintenance of the equipment.
Reverse Osmosis
This is a process that is often
described as filtration, but it is far more complex than that.
We sometimes explain it as a filter because it is much easier
to visualize using those terms. We should remember that osmosis
is how we feed each cell in our bodies: As our blood is carried
into the smallest of capillaries in our bodies, nutrients
actually pass through the cell wall to sustain it's life.
Reverse osmosis is just the opposite: We take water with "nutrients"
(in this case, junk) in it, and apply pressure to it against
a certain type of membrane, and, presto -- out comes "clean"
water. Lets review the basics: If you take a jar of water
and place a semi-permeable membrane (like a cell wall? or
a piece of skin?) in it, dividing the jar into two sections,
then place water in both sides to an equal level, nothing
happens. But, if you place salt (or other such substance)
into one side of the jar, you will notice that, after awhile,
the water level in the salty side begins to rise higher as
the unsalted side lowers. This is osmotic pressure at work:
The two solutions will continue to try to reach the same level
of salt in each side by the unsalted water passing through
the membrane to dilute the salty water. This will continue
until the "head" pressure of the salt water overcomes the
osmotic pressure created by the differences in the two solutions.
On the other hand, researchers have discovered that if we
take that membrane and feed water with sufficient pressure
to overcome the osmotic pressure of the two waters, we can
'manufacture' clean water on the side of the membrane that
has no pressure. We sometimes say we "filter" the water through
the membrane. Depending on the membrane design, and the material
it made from, the amount of TDS (total dissolved solids) reduction
will range from 80 to over 95 per cent. Different minerals
have different rejection rates, for instance, the removal
rate for the membrane I am looking at now is 99.5% for Barium
and Radium 226/228; but only 85.9% for Fluoride and 94.0%
for Mercury. Removal rates are very dependant on feedwater
pressures, and some membranes are not tolerant to high or
low pH. For home use, it is important to make sure you get
an RO *System*; ie, a sediment prefilter, a carbon prefilter,
membrane, storage tank and post carbon filter. Some of these
filters may be combined into one, ie, the prefilter may be
a particulate and carbon both. A lot of comments have been
made concerning the *wasting* of water by an RO. True, the
old style units with the early type membranes were more prone
to becoming plugged, or fouled by the "junk" they removed
from the water. To help keep this from happening, a small
amount of water was allowed to run across the membrane to
help carry away those impurities to drain. Early designs only
recovered 1 gallon of good water for every 4-8 gallons used
to keep the membrane clean. Even worse, when your storage
tank was full, water still ran to the drain because the early
membranes were made of a material that the little bugs in
your water supply (no, not pathogens, or dangerous to you
in small numbers) loved to eat! So to prevent that, we just
let the water run so they couldn't have time to stop and eat.
:>) Now membranes are made to not only recover a much higher
percentage of the feedwater, but the bugs don't eat them!
Newer systems not only recover more, they can have a shut
off device that stops all water flow when the storage tank
is full. Actual recovery rate is dependant on several factors,
including the TDS, and just what the TDS is composed of, in
your feedwater. Temperature, pressure also have a big effect
on the amount of product water you can make in a given period.
Remember, all RO units are normally rated using a feedwater
temperature of 77 degrees F -- is your feed water temperature
that high?
What is the best water for Coffee?
Well, that a good question! After
visiting with many coffee people, I have gathered the following
as a basis for recommending the "perfect water" for coffee.
1. All oxidants removed. (Chlorine or other such sanitizers".)
2. All organics removed. (You know, dead fish, tadpoles, THM's,
insecticides, pesticides, etc)
3. TDS (total dissolved solids) from 60 to 100 ppm (parts
per million)
4. Hardness of about 3-4 grains per gallon. (51.3 to 68.4
ppm)
5. Low sodium water, ie, less than 10 mg/L.
6. pH depends on the Bean you are using, plus the method of
extraction.
7. Iron, Manganese and copper gone, or less than 0.02 ppm.
What is the best way to get this
type of water?
There is no single answer for
this question, however, if we assume you are getting your
water from a municipal supply, we *assume* the Iron and Manganese
problems are taken care of by the city plant. (Some towns
may not solve these problems -- you be the judge!) Copper
*may* come from the supply itself, or, if the water is aggressive
enough, it may actually be picked off the copper plumbing
in your house as it sits overnight in the pipes. (Lead can
also be leached out of the older "sweat" joints that may have
used solder that contained lead.) It is best to "clear the
pipes" the first thing in the morning before using any water
for ingestion. Simply run enough water to clear your pipes
of the 'overnight' standing water that *may* have picked up
the harmful metals from your pipes -- use it to water your
houseplants. If we use a good, properly sized carbon filter,
we will substantially reduce the organics and oxidants in
the water, as well as remove most of the particulates. However,
we still have TDS and Hardness to worry about. If we soften
the water, we do not reduce the TDS, we simply *exchange*
the hardness minerals for Sodium -- which we don't want for
coffee! The best answer (usually) is the reverse osmosis system.
This *system* usually has a particulate and carbon filter
(organics, oxidants and particulates are reduced); and a membrane
(reduces the TDS by about 90% -- including hardness, sodium
and others as well); all linked together in one flow path.
We can greatly improve the coffee by using any one of the
above mentioned methods, but if we combine them, we get, for
all practical purposes, the *best* water for your coffee!
Rule of thumb: With an RO System, whatever impurities were
in the water are typically reduced by 90% or more, leaving
only water behind, which is what we really wanted, anyway!
How much sodium does Ion-Exchange
add to my water?
For every grain of hardness in
your water, 7.5 mg of Sodium will be *added* to each quart
of water by the ion-exchange method. If you have water that
is 10 grains per gallon hard; you will add 75.0 mg of Sodium
per quart of water softened by ion-exchange. To put that in
perspective, one 8-oz glass of milk contains 120 mg of Sodium,
one slice of white bread contains 114 mg of Sodium. You must
also remember that there is *probably* Sodium in the raw water,
too. If your city supply treats your water by a "hardness
reduction" treatment plant, you can be sure that the Sodium
level in your water has increased as a result -- how much?
Call your plant operator and ask -- it is information free
to the public.
[ Back to Table
of Contents ]
Water Testing Information
When Should I test?
Several factors will influence
when and how often you test your water. Where do get your
water from? Has that source changed? Have you done any plumbing
changes lately? Is there reason to believe that your water
is contaminated? Is there a sickness or illness in your family
affecting more than one person and over a longer than normal
time period?
If you receive your water from a "Public Supply", ie, a municipal
supply, or a supply that provides water to more than 25 persons
for 60 days per year (some states are different -- check with
YOUR local water department), you can be fairly certain that
the water supply is checked on a regular basis. The frequency
of the testing is based on the number of people served, and
may vary from more than once per week to once per month, or
even less. Under these conditions, test when you move into
a new residence to acquire a "base line" of contaminant level,
if any. Retest every three years, unless you have reason to
believe that something has changed that could affect the quality
of your water.
If you have a private well, you are the only person who is
responsible for the water your family drinks and bathes in.
I recommend testing by your local Health Department every
six months for Bacteria and Nitrate. These two tests serve
as indicators for other types of contaminations -- that is
not to say forget the other tests; just that if you get a
"bad" test from them, you should also retest for the other
types of contaminants as well. Private wells should be tested
on a regular basis for Pesticides, Herbicides, Metals, Organic
and Inorganic chemicals and volatiles. Currently, no laws
govern the frequency of such testing -- that is why I say
YOU are the only person responsible for your family's water.
I recommend an initial test (for a base line), and then at
least once per year. Remember, one day after testing and finding
"no contaminants", your source could become contaminated.
What Could I Test For?
Coliform bacteria are a group
of microorganisms that are normally found in the intestinal
tract of humans and other warm blooded animals, and in surface
water. The presence of these organisms in drinking water suggest
contamination from a surface or shallow subsurface source
such as cesspool leakage, barnyard runoff or other source.
The presence of these bacteria indicate that disease-causing
(pathogenic) organisms may enter the drinking water supply
in the same manner if preventive action is not taken. Drinking
water should be free of coliforms.
Cysts and viruses are microbiological contaminants, usually
found in surface water supplies. Giardia lamblia cysts can cause giardiasis, a
gastrointestinal disease. Another "bug" getting a lot of attention
lately, is cryptosporidium, single-cell parasite
measuring about 2 - 5 microns in diameter. Many surface water
supplies contain this pest, which also comes from the intestine
of warm blooded animals.
Nitrate in drinking water supplies may reduce the oxygen carrying
capacity of the blood (cyanosis) if ingested in sufficient
amounts by infants under 6 months of age. This could cause
a disease called "methemoglobinemia", or "blue baby" syndrome.
The EPA has established a maximum contaminant level (MCL)
for nitrate at 10 mg/l (ppm) measured as N. Unlike coliform
or other types of bacteria, boiling the water will actually
INCREASE the amount of nitrate remaining in the water, increasing
the danger to infants. If you have high nitrate water, either
treat it with an approved treatment metholodgy or find another
source: Boiling will only make it worse!
Lead is now known to leach from older sweat joints in copper
pipe. As the water sits in the pipes, small amounts of lead
'dissolve' into the water, contaminating it. Lead is particularly
harmful to small children as they more rapidly absorb the
toxic substance into their systems. The EPA has estimated
that more than 40 million U.S. residents use water that contains
more than the recommended levels.
An Easy Way to Test
National Testing Laboratories,
Inc. in Ypsilanti has a five bottle testing kit, which is
supplied by many water quality professionals across the nation.
You simply follow the directions in the kit and return the
sample to the lab. They test your sample and then report to
you. Your test results will be a two page report showing contaminant
level, a cover letter explaining the test results and what
you should do.
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