I have a whole house Aquat water softner and filter system (new system that was put in last week). I believe the incoming line is connected to the filter, then the filter output line is connected to the water softner. The water softner output line is connected to the house.

I believe both the softner and the filter has drain lines that are plugged into the drain/sewage pipe.

Currently, the filter is working nonstop and I can hear tons of water being flushed down the sewage line. The plumber shut it off but will be back next week to fix it (he will need to contact the company cause he doesn't know what the problem is).

My question is.....is it possible for the sewage pipe to backwash into the filter system? Are there any engineering/plumber standards to prevent this? (do you think the system has this in place?)

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    It would be tough for the sewer to back up in only 1 pipe. Are you having any problems with showers / tubs draining or backing up? These are normally where the problem would show first. I looked Aquat up and it said no waste water no salt so I would wait for the company response. – Ed Beal Feb 27 '16 at 15:06
  • Can you post photos of the how the drain lines are connected to the waste system? – ThreePhaseEel Feb 27 '16 at 17:06
  • Here is the photo of the entire system: drive.google.com/open?id=0By7XFUbeHnu5dzN4RFpsZjZsaHM On the left, the black tank is the softener salt container. The middle tank is the water softner. The right tank is the water filter. Here is a photo of the lines going in and out of the system: drive.google.com/open?id=0By7XFUbeHnu5c25lR1NyRDRNbms – montisqu Feb 27 '16 at 22:18

This should not be a concern in a properly designed system, short of a flood. If you're feeling especially paranoid you could put an air gap in that drain line, but ...


Sounds like this system was not installed properly. When these filters are installed it is essential to set the heads on each tank for proper recycling which should only happen each alternate night (usually between midnight and 5 am or so ) If you are hearing it working constantly then something is not set properly. < You should call the installer back and get him to fix it. If the plumber or even you do it, it will in most case void the warranty. > May not be relevant in this case, but YES there should be an airgap of about 1/2 inch below the drain lines. In your photos I could see no evidence of a By-pass pipe and valve. Any reputable installer will do this in case of problems with the system. Yes, I know there is a By pass knob on rear of each head, but this is not really adequate.


Sounds more like the either the timer motor or piston drive motor is stuck in backwash. Either due to a mechanical failure of the gfci that it's plugged into tripped. But as long as there is an air gap between the sewer and the drain pipes then no possible way to back up into potable water system. If the drain lines are shoved down a standpipe like behind your washing machine. It may not be code but as long as the hose is not sealed or so tightly packed that the water can not rise and escape around it. Your ok. I know this may not be up to code but here in the real world we want to know is the sewer going into my water softener. So far no. If the drain line heads up into the attic or is sealed into a drain pipe remember gravity and he path of least resistance. If there is even one open drain lower than the drain connection in question the water will evacuate at the lowest possible place There is always a chance that the perfect storm could arise and alll the pipes are clogged except this one then yes. It's possible if they are directly connected In 10 years I never saw that happen except in one instance there was an ro system used only for the refrigerator water supply. The previous company cut corners or improperly service the unit a black bacteria started growing back from the drain to the reject side of the membrane and here is where RO earns its stars. The bacteria could not permeate the membrane instead it worked its way down the membrane to the feed line and down to the last pre carbon filter and was living off that. It couldn't go any further because the water on the feed side to the carbon filter is sanitized by the municipality THIS VERY REASON IS WHY : Sanitization is required there is no magic trick to get around this. Please have a professional water quality expert service your equipment yearly. More frequent intervals are only necessary if the usage of the system is higher. But your typical family /household use once a year will suffice waiting longer especially because you don't use the system or the system is turned off is not a good idea , it is even more important citing My above mentioned story was due to low flow and low use situation. I understand that it costs money and as a professional it is my responsibility to look out for the customer too, and it is understandable that sometimes the budget gets tight and sacrifices are made. I've never been opposed to educating my customer how to do his service themselves. Both me. And women are capable of changing a set of filters each year. And it's a cost effective and relativly safe way to turn this service into a bi annual visit. I'd recommend still having your local pro come out because parts wear out and we have laid our dues. Let it be understood we have paid our dues. We know the hazards that await us and without fear of flood we move along. A few things to this original poster

Depending on the make and model and age of your system. Just shutting it off is not a viable solution. There is. Proper procedure for putting the unit in bypass and there are serious steps that must be take. To avoid potential catastrophe. Such as flood of completely ruining your sometimes expensive system when all that was needed was a cheap clock motor. I'm not saying the plumber did wrong. But a water quality technician isn't a plumber although we do some of the same things in as a plumber is rarely a qualified technician.


Here is a few things relevant

Air gap should be at a distance equal to the diameter of the pipe. A 1" pipe needs a one inch gap 3/4 a 3/4 gap ect

Unplugging the controls is not putting the unit in bypass and turning the bypass could have consequences. Know what your doing first.

Water running down the drain 24hours day is a problem. Hearing water run down the drain is not. Even if it seems to be running for hours. The full regeneration cycle takes 3-4 hours depending on the model. And some units especially those you find at a home improvment or club card store. Are very low capacity they very easily could need to regenerate as often as every 1 or 2 nights. This usually happens at night but if the power goes out causing the time of day to be off , or the valve is programmed wrong you might end up hearing the regeneration when you normally wouldn't. I bet you will come to find there is nothing wrong with your softener it will be either a power issue. Outlet or motor A programming error , time of day is wrong , or faulty meter , possibly a bad piston motor or striped gear leaving the softener in a regeneration stage. This will waste water but will not affect your water because the unit bypasses itself internally while regenerating. Call your local pro and get someone reputable out there to look at it. I garuntee your plumber has already recommended you get a new one he can install. Which although cheap is a lot more than the 20 dollar part and at worst 100 call. Most plumbers know a good water guy. If you're doesn't. I'd check to see how long he has been plumbing and why doesn't he network with the other trades. I am a water quality tech in Arizona But don't call me for plumbing needs I'll send the guys I would use. Need an appliance repair. I got that guy too. Why because we do the same type of stuff and sometimes our jobs overlap and intertwine. But you don't want me to set your subzero. Get the right guy for the job. You wouldn't drive a nail with a chopstick. Would you?


Also this is NOT just the installation of the system. And the installer is NOT NECESSARILY to blame. Without a picture of the drain line we don't know if it's up to code. Be that as it may the drain only comes into question because water is heard running down it. Ok. There are so any reasons for this I can't list the. All Plus some fixes you have to pay your dues to know about. Your plumber will mis diagnose this I already know it. ( my other posts have possible solutions) but there are a large number of possibilities I assure you. The original problem is the water is going down the drain excessively (per the normal operation as opposed to an individual PERCEPTION of excessive draining) 24hrs a day is excessive 2-4 hours is not. If you want me to explain the regeneration cycle feel free to contact I can tell you how much water is used how much salt is needed and how long that salt needs to contact the resin bed. There is so much mis information about this technology is mind blowing. And I look forward to squashing the people who kinda know. But don't and keep perpetuating this bad info. Save money and save water save the landfills it's our community and our water. Our sustainability. Deserts of the southwest to the farms of the plains and on it is important we get it right.

  • It's better if you edit your existing answer to add more information, rather than add a second answer. It's also a bit difficult following what we call "wall of text" answers; adding some paragraph breaks can really make a good answer easier to understand. – Daniel Griscom Mar 30 '16 at 11:58

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