| Who
needs a whole house reverse osmosis system and what does it cost?
Whole house reverse osmosis systems are usually used when the
water source is really bad. Most municipal sources are not that
bad and usually, just filtering, softening (if required) and adding
and under sink reverse osmosis system for drinking water is enough
to make everybody happy. Where I live the water is very hard and
the total dissolved solids is about 600 ppm (parts per million,
lake Michigan is 80 ppm, the ocean is about 35,000 ppm). We run
a big blue (4.5" x20") filter rated at 20 microns followed
by a carbon filter (chlorine makes my wife itch) and an under
sink reverse osmosis with a 3 gallon bottle in the kitchen and
one in the bedroom that we fill as needed for drinking water.
Most of the reverse osmosis water is used for the orchids. If
you dechlorinate your water, there will be bacteria growing in
your toilets eventually. It is not harmful but you might dump
a capful of chlorine in the tank once a month or so to kill the
bugs.
To just filter a house and add an under sink reverse osmosis
and water bottles should be less than $500.00 (US). The standard
reverse osmosis system will remove heavy metals, bacteria, and
cysts, the standard problems, down to acceptable levels. Viruses
will pass the membrane but so far, in the USA, viruses in the
water have not been a health issue and hopefully they never will.
If your water source is chlorinated or you have a deep well, pathogens
should not be a problem.
People who buy a whole house system are usually on a well
and building a new house so the cost can be added to the mortgage.
The wells usually have a very high dissolved solids level
or other issues that make them undesirable for drinking.
Issues with whole house reverse osmosis systems.
1. Noise - Place them away from the bedroom. After everyone
showers in the evening, the system will kick on to fill the
tank and the pump will make noise. If you get a 1 gpm system,
and you use 120 gallons of water showering, flushing, brushing
your teeth, you will have a 2 hour pump run. If you have a
teenage daughter like mine, you will have a 4 hr pump run
and no hot water for your shower.
2. Cost - You will run 2 pumps, one to feed water to your
house when you need it and one high pressure pump to fill
the holding tank. If you need a softener, you will have to
purchase salt and maintain the softener. You will have to
replace the membrane every 3-5 years if it is maintained correctly
(more often if you ignore the system).
3. High recovery reverse osmosis systems have a concentrate brine
discharge that you will have to deal with. If you have 600 ppm
going in and reduce the tds to 10 coming out and get a 50% recovery,
the brine will be around 1200 ppm. If it is 66% recovery, you
will approach 1800 ppm. This is too high for most irrigation needs
and septic system. It is not suitable for stream discharge you
you will need a separate leach line for the discharge.
Whole house reverse osmosis systems costs vary with the water
quality and your needs. Get a water analysis first!
1. The basic system consists of controls, membrane and housing,
high pressure pump and motor, 2 pressure gauges, 3 control
valves, 3 flow meters, low pressure switch, conductivity monitor,
and mounting skid. We build the high pressure system out of
stainless so we never have to worry about leaks or service
problems.
2. A whole house reverse osmosis system will have flows lower
than the flow rate to the house so you will need a holding
tank, pump and bladder (pressure) tank to feed the water to
the house.
3. If the water has high calcium or you want to recover a major
portion of the well water, you may need to remove the calcium/magnesium
(hardness) with a softener. You may also use a polymer or acid
feed to minimize hardness problems in the system. Usually, with
high hardness, a polymer addition system is much less expensive
to run than a softener but it takes more attention than a softener.
4. If you live in an area where there has been volcanic activity,
the silica may be high in the water and that may limit the
recovery rates. Don't plan on an 80% water recovery rate.
Costs -
1. Reverse Osmosis mounted on skid with recycle loop, prefilter,
all kinds of neat stuff to make it work. Approximately 6,000.
USD for 1 gpm. Set up to interface to following items.
2. Water storage and repressurization system with pump and
bladder tank mounted on RO skid. Includes integrated level
control for reverse osmosis system. Costs run $2000-4000 depending
on tank size, pressure required and flow rate.
3. Water softener if required. Sized to regenerate after
set flow volume. Integrated to RO controller to prevent hardness
bypass during regeneration. Available as dual system. Cost
base on water analysis, usually runs $800-3000 depending on
water quality.
4. Polymer addition system to sequester calcium. Used instead
of softener. Costs about $000-1200 per unit.
5. Installation - plumbing and electrical. Depends on local
rates but it should run $300-400 total.
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