I'm looking for folks with experience using a reverse osmosis system in a
home with a deep well and on a septic system. The deep well is a typical
20-40 psi system. From what I've been able to determine, RO systems require
a relatively high incoming water pressure and, even with a good water
pressure (say 55-60 psi) a lot of water is bypassed to the drain.
Is there a potential problem using an RO system in this situation? Is there
enough bypass water to cause problems with a septic system effluent field?
How about if I install a booster pump to push the water pressure to the RO
unit to 65 psi?
if you have a sumersible pump you should be able to set the pressure up
to 60 psi at the tank have someone who does well service in your area
check it to make sure the pump is sized properly to deliver the
additional pressure. they should be able to check it with just a
standard service call fee scott
I thought of using it for laundry too, but a chemist told me that the
higher mineral content of the effluent makes it like hard water, with
all of hard water's problems. The turds can't tell the difference,
though. I also use it for dust control in my business, and in the
pressure washer for cleaning mud off equipment.-Jitney
I haven't installed the system yet and I'm trying to determine what I'm up
against, if anything. It's claimed to be a 100 gallon per day unit and it's
not all that expensive. I plan to use the system only for drinking water
and an ice maker.
I've done some reading on the web and, of course, there are some conflicting
statements. For example, one site says that a minimum of 35 psi is required
and that at lower pressures essentially no water is forced through the
membrane and all of the water goes to the drain. They go on to say that the
higher the input pressure, the better the ratio of pure water vs. bypass
water going to the drain. Thus, on a deep well system they recommend a
booster pump to get the input pressure above 60 psi.
There's also a gizmo that supposedly substantially reduces the water going
to the drain called a permeate pump. These folks claim that some RO systems
can drain 10 gallons to waste for each gallon of pure water produced. The
claim is that a permeate pump will reduce the wasted water by up to 80% and
will also extend the life of the RO membrane.
Some manufacturers claim that an RO membrane by itself will eliminate over
99% of bacteria and viruses while another manufacturer says that you must
have an ultraviolet treatment filter to eliminate bacteria and viruses.
I have considered running the waste water somewhere other than the septic
system. Probably a storm drain.
Oh, yes, and another thing. Some manufacturers claim that you shouldn't use
a DI filter in a drinking water system. Another site claims that you can
use a DI filter if you have a taste and odor filter downstream from the DI
One site I visited even claimed that you shouldn't use a DI filter in a
drinking water system because if you use the DI filter you essentially
remove ALL if the impurities from the water and that will adversely affect
the taste of the water. I thought RO was supposed to remove nearly all of
the impurities (dissolved minerals) from the water. I realize that nothing
will remove ALL of the impurities, even triple distillation. I'll have to
admit, I worked in a lab once that had an RO system with DI filters
afterward, followed by a UV treatment stage. I tasted the water once and it
did taste off, kind of flat in my estimation.
A typical RO system can make about 30 gallons of water per day. If it
does that, it also wastes another 30 gallons of water. However, if you
don't use any filtered water, so the RO tank is full, you will waste
the entire 60 gallons.
If you have an automatic shut-off valve installed, this will turn off
the input water to the RO system when the RO tank is full. That stops
any additional water waste. In that case you only waste as much water
as you actually use, which is probably much less that 60 gallons/day.
This will not only reduce load on the septic system, but also on the
I don't think even 60 gallons per day would be a problem for a
properly sized septic system.But there is no reason you need to drain
the RO system into the septic system. If you have a sump pump in your
basement, drain the RO system into it.
I had a problem with my system not having enough pressure to activate
the shut off when the tank was full and the discharge line ran
continiously. (On a well with the pump shutoff set at 50 psi.)
I obtained a permeate pump from http://www.waterfiltersonline.com/ and
it solved the problem. It works by using the pressure from the
discharge to increase pressure of the source water. The tank now
pressurizes fully and the shutoff works properly.
My understanding is that a r/o system works better after a sodium
exchange water softner. They reject sodium easier than calcium and you
are less likely to get scaling of the membrane.
Some are concerned about bacteria with r/o and if your water is
contaminated it will concentrate in the filters. The r/o will filter
95% of nearly everything on the ionic level (ie. sodium and chloride
ions). I have a conductivity meter (measures in microsiemens) and have
confirmed this % cleanup and better with r/o systems. Bacteria and
viruses are larger than sodium ions and 95% are filtered out. Its the
5% remaining that you have to worry about. I personally feel that its
an improvement on the water you start with and as long as you change
your primary and post filters regularly and don't leave the water in
the system sit for weeks without use you will be alright. Bacteria can
grow in filter media if they get a good foothold. 15 years drinking
r/o and three houses on a well and no problems. Your mileage may
The waste water is "white water" vs gray or black water, I don't run
my laundry, softner discharge or r/o reject into my septic. (softner
discharge is also considered white water, laundry is gray) What you do
with this water is another topic and can be restricted in some areas.
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