Ask Me Help Desk - Drain with back pressure

I have a conventional sceptic system with two tanks - each serving one wing of my house.

My laundry room deep sink drain has pressure on it, enough to raise the water level in the sink about 10". This happens even when there is no water running down any drains connected to this wing - I even checked the condensation runoff line from my AC drain pan.

When I remove the p-trap for the laundry sink, it trickles "uphill" to where I have to put a bucket underneath of it to catch the water. I had the sceptic tank pumped (which I really needed to do anyway...) and I was sure that the pressure would go away until at least the tank filled up to the drain field exit line. Still water coming "uphill".

Water appears to be graywater - not pure sewage.

I've never been so perplexed in my life. Windyman

There are two things that would cause this problem. One is back fall that leads to a trap being formed in the line as well as making the drain seem to run backwards. The other is a partial blockage that allows the water to build up in the line and back up into a trap. Both needs a man on the site to check it out. How much "gray water" comes out of the trap before it stops?
Regards, Tom

Quote:

Originally Posted by speedball1

There are two things that would cause this problem. One is back fall that leads to a trap being formed in the line as well as making the drain seem to run backwards. The other is a partial blockage that allows the water to build up in the line and back up into a trap. Both needs a man on the site to check it out. How much "gray water" comes out of the trap before it stops?
Regards, Tom

I'm not aware of any other drains being backed up and I have shut off all usage of water in this wing to make troubleshooting easier. I even checked the two toilets to ensure no leakage around the rubber flapper. There is no water entering this drain system yet, when I remove the p-trap for this drain, the trickle NEVER ends. It fills a 5 gallon bucket in about 5 hours.

If I reinstall the P-trap, the water level rises in the sink until the pressure on the drain from the water column in the sink equalizes with the back fall pressure.

Am I supposed to type before your "quote" or after. I'm new to this... Jim

Just hit the quote button and type underneath.
Well the water's getting into your drainage system from somewhere. Have you checked the pointer on your water meter after shutting off everything in the house to see if it's entering that way? Have you opened up both cleanouts to the septic tanks to see if the line was clear and not backed up?
Somewhere, somehow you're getting a steady stream of water iunto your drainage system and you're going to hafta track it down. I wish I were your plumber. This is just the kind of complaint I love to sink my fangs into. Please keep me in the loop and let me know what you're doing. Good luck, Tom

Quote:

Originally Posted by speedball1

Just hit the quote button and type underneath.
Well the water's getting into your drainage system from somwhere. Have you checked the pointer on your water meter after shutting off everything in the house to see if it's entering that way? Have you opened up both cleanouts to the septic tanks to see if the line was clear and not backed up?
Somewhere, somehow you're getting a steady stream of water iunto your drainage system and you're gonna hafta track it down. I wish I were your plumber. This is just the kind of complaint I love to sink my fangs into. Please keep me in the loop and let me know what you're doing. Good luck, Tom

You and I both wish you were my plumber. Do you install anaerobic sceptic systems? If so, you might want to come to Rockwall (East side of Dallas). That job would be big enough to make it worth the trip if you want at this problem. You're most recent response is EXACTLY what I felt you would tell me because determining the souce of water being introduced to the drain system is clearly the mystery that is centric to this problem.

When you say "shutting off everything in the house", do you mean stopping all water from entering any of the drains in either wing? Are you envisioning bleed from the water meter valve finding its way directly into the drain system? How could this happen? Would the meter gauge pointer be sensitive enough to detect 1GPM bleed? The pool is on the same side of the house but I can't imagine anyway that it would be anything but a closed loop.

Regarding the sceptic systems, even if the sceptic tank line was backed up, Would there be enough water column in the drain system to cause enough back pressure to push water back into a sink (previously 10-12" - this AM its only 1" after I monkeyed with everything all day yesterday).

PS, I suspect the blockage is ceiling popcorn from the idiots that painted our house several years ago. I plungered the out of the drain when I first found the problem a month or so ago and I got popcorn pieces to regurgitate back into the sink. I tried snaking the drain but with no luck becaue this particular drain goes lateral (parallel to the floor) 5-6 feet (not sure because its behind a wall) before teeing into a vertical drain.

"When you say "shutting off everything in the house", do you mean stopping all water from entering any of the drains in either wing? Are you envisioning bleed from the water meter valve finding its way directly into the drain system? How could this happen? Would the meter gauge pointer be sensitive enough to detect 1GPM bleed?"
I meant shutting down all fiixtures so that nothing's running in the house and checking the pointer for creep. And yes, if water were leaking past the meter into the house the pointer would show it.
Something's putting water into your drainage system with enough pressure to raise the level 10/12 inches. Now this pressure could come from a outside source such as your meter or it could be head pressure that's being built up in your drainage system. Is your pool drain tied in to the sewer? Is the pool grade higher then the house? Do you have AC condensate drains, sump pump drains, water softener drains, etc. connected to the sewer system? (This is against code in my area.) Do not overlook any possibility in checking this out.
As for making a service call to Texas I'm a 80 year old that's been retired since 1988. I just want to pass on some of what I've learned over the years spent out in the field. Regards, Tom

Quote:

Originally Posted by speedball1

"When you say "shutting off everything in the house", do you mean stopping all water from entering any of the drains in either wing? Are you envisioning bleed from the water meter valve finding its way directly into the drain system? How could this happen? Would the meter gauge pointer be sensitive enough to detect 1GPM bleed?"
I meant shutting down all fiixtures so that nothing's running in the house and checking the pointer for creep. And yes, if water were leaking past the meter into the house the pointer would show it.
Something's putting water into your drainage system with enough pressure to raise the level 10/12 inches. Now this pressure could come from a outside source such as your meter or it could be head pressure that's being built up in your drainage system. I'll check - the water meter is tough to get at....How else could a drain system get head pressure? We just had the sceptic tank drained so I shouldn't have any back pressure from the sceptic for a while. The most likely sceario for me is that I have a blockage upstream from the main entrance to the sceptic tank. When a toilet flushes or someone introduces water to any drain on that wing, Head pressure builds and the water column in the overal drain builds. What do you think of this theory? My house was built in 1973. Do you have a feel for how the line(s) would go into the sceptic tank? Is there only one line (4" presumably since there are two toilets in the drain line) going into the tank or can there be several lines entering the tank?Is your pool drain tied in to the sewer? Is the pool grade higher then the house? Do you have AC condensate drains, sump pump drains, water softener drains, ect. connected to the sewer system? If my pool is connected, I'd have no idea how. The backwash line goes directly to a separate drain tile line that emties directly into a gully. The pool is below the house grade and if its above the sceptic tank entrance pipe grade, it is not obviously so. AC condensate drains (remember I already check this) go directly to the ground by dropping straight to the ground through an eve.(This is against code in my area.) Do not overlook any possibility in checking this out.
As for making a service call to Texas I'm a 80 year old that's been retired since 1988. I just want to pass on some of what I've learned over the years spent out in the field. My folks live in Northport. Very nice of you to give back!. I'll take you out to dinner and hug your neck next time I'm down there. Jim SteedRegards, Tom

Jcs