Septic tank connection to drainpipe

[JB4310]

Yup as the two previous posters stated you need some kind of a baffle to prevent the floating crap (when can you ever use that word as the literal definition ) from skimming off the top and fouling up your leaching system in short order.

Still find it hard to believe someone would go through the trouble of installing a septic tank with no leach field. What did they do have a flush counter, so they would know when it was full?

JB.

 

[Highbeam]

We get lots of folks putting in "holding tanks" for site that aren't good for septic or if it is just a temporary deal. It turns out that a septic tank is very cheap to buy and have set. Down around 70 cents per gallon vs. most tanks at over 1$ per gallon. They're good tanks but not usually put in without a drainfield because the local health departments don't consider it a permanent solution to have to pump out the holding tank occasionally.

If it was me, I would have an overflow to show me when it was too full but also would check it often through one of the smaller baffle access lids. Nothing is worse than sewage backing up.

 

[MarkV]

Every place is different so this may not apply. In my area 1000 gals of tank and 150' of field is minimum. Doesn't matter if you are talking never used, barn bath or full time small house. Could be a big issue if it were disclosed, as required in a future sale.

MarkV

 

[bcarwell]

Thanks again ! Tommu56 and Highbeam: what is the purpose of the upper part of the T going up ? Why isn't it just an elbow joint facing down ? Seems the scum layer could rise up above upper part of the T and run into the T and out into the leach field. I'll feel for the T when I knock out the punch out on the side of the tank as I'm wondering if even my little cheapo 500 gallon septic tank would have such a T or would they expect you to add it if you are adding an output/leach field line. And I'll have to try that "hydraulic cement". Never heard of it before ! BTW a semi plumber type guy at Lowes said to seal with that expanding foam stuff and said that's what they use. Is he right or is grout the preferred sealant ?

 

[Western]

One thing I wish we had added to ours was a junction box or manifold (not sure of the proper term) Basically an access point between the leach field and last tank.

Someday I may have to add a floating foam or crystal root killer and that would eliminate going through 2 tanks.

 

[JB4310]

Thanks again ! Tommu56 and Highbeam: what is the purpose of the upper part of the T going up ? Why isn't it just an elbow joint facing down ? Seems the scum layer could rise up above upper part of the T and run into the T and out into the leach field. I'll feel for the T when I knock out the punch out on the side of the tank as I'm wondering if even my little cheapo 500 gallon septic tank would have such a T or would they expect you to add it if you are adding an output/leach field line. And I'll have to try that "hydraulic cement". Never heard of it before ! BTW a semi plumber type guy at Lowes said to seal with that expanding foam stuff and said that's what they use. Is he right or is grout the preferred sealant ?

Not to speak for them, but but the reason for the tee is, easier to inspect and clean if necessary, and possibly acts as a vent like in the house to prevent siphon, but not sure about that. The 90 would work but would not be easy to clean and inspect. The old tanks I've seen just had a steel plate across the opening acting as the baffle.

You could have a short riser on it to prevent any high floating stuff from going over the top, but the water level would stay at the height of the bottom of the pipe, which is about 6 inches from the top of the tee. Not sure but some may have a riser up to ground level, that would make for easy inspection.

So I take it you have not uncovered the top of the tank to look in there? As far as if there is a tee now in there, I am not familiar with modern septic systems, but would suspect that if knock out is not stubbed for pipe and is designed to slip pipe thru, that there may not be a tee in there. Though you did mention there is that collar or flange built in, so maybe there is something in there.

I personally would pump the level of the tank down before I knocked that plug out or stuck my hand in there for inspection, sounds like an episode of "Dirty Jobs"

JB.

 

[tommu56]

the top of te tee should have a 12" piece of pipe in it when some one flushes toilet you want to be able to see the effluent going up the lower leg of the tee and out the side by looking down the the upper section.

don't use foam for the seal use a sealer gasket or hydraulic cement.

as JB4310 pump tank down slide pipe in through knock out glue tee assembly on pull it back out some but so you can see down manhole and see the tee.

some times there is some sort of baffle is cast in side the tank to eliminate the tee thingy

tom

 

[Highbeam]

My tee doesn't have a stub running up. Just the top of the tee which is where I shove in the effluent filter. The scum level should never come up in the tank. The scum is only slightly less dense then water and will displace water to almost the level of the bottom of the outlet pipe. That outlet pipe should always remain either empty or flowing out at the exact same rate that it flows into the tank through the same size 4" pipe. So You should not expect the level of the tank contents to rise and fall at all in the tank meaning that you don't need a top riser.

Truth be told, I take good care of what goes into my tank and my scum layer has only ever been 1/4" thick and missing in places. Scum is fats, oils, and grease and you shouldn't be dumping that down the tank. It slowly will be digested as well so some input from people washing and dishwashing will make it to the tank only to be digested. In my case, the sludge from below accumulates fastest.

Oh yes, it needs to be a tee. The drainfield must remain aerobic to provide secondary treatment. It needs air moving through it and the drainfield will vent into the septic tank which vents out through the stack vent in your house. Do not use a 90.