Septic Tank with Pump Tank - Venting?


Old 08-21-18, 09:09 PM
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Septic Tank with Pump Tank - Venting?


My pump (effluent) tanks pump got blown out by rain water getting into the outlet (installed at ground level and not water tight...idiots) and fried the outlet and pump.

The tank lid is a concrete frame, cracked in three corners with gaps over an inch wide and the concrete lid (which takes 2 people to lift) moving lower and lower into the frame as it separates. Let's also mention the rebar handles on either side of the frame that are broken in half and sticking out at odd angles just waiting to stab someones foot!

So, I figured while I was changing out the pump, I might as well take the opportunity to rid my backyard of this unsightly safety hazard.

I got the PolyLok system with the square tank adaptor ring and riser.


The PolyLok riser and lid come with pre-installed gaskets to make the connections water and air tight. The instructions for the square adaptor ring also say to seal the ring to the tank with caulking or their own gasket material.

Given this and my lack of complete understanding of how my septic system works, I'm wondering if it's ok to make a water and air tight seal on the pump (effluent) tank? Do I need to add a yard vent (none are currently present nor has there ever been to my knowledge) or should the system be set up to vent through the roof (I do have two pipes on the back side of my roof)?

Obviously the current lid setup is nowhere near water or air tight, allowing gasses to be vented through the cracks and gaps. So before I seal it up, I want to make sure I'm not creating another issue down the road with gas building up in the pump (effluent) tank.

Side Note: I'm also installing a new outlet to sit above ground level with a weather cover.
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Old 08-22-18, 05:09 AM
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Check with your local septic tank manufacturers. Many of them make a Polylok riser adapter. They pour a round or square concrete slab about 4" thick around the base riser ring. The extra weight of the concrete makes it much easier to keep the riser in place and to maintain a watertight seal with the tank. I normally use a thick, sticky bitumen/tar like caulk to seal it to the tank.

I would not install a separate vent. It's just one more thing to hit with the mower. In all honesty I've never seen a system seal well enough to be air tight enough to cause a problem. If you want you can remove the gasket from the lid so air can enter if your lid is above ground.
Old 08-23-18, 07:54 AM
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Not sure we're fully on the same page.

I have the PolyLok riser adapter with the sticky tar like seal and bolted it to the tank with masonry anchors.

My question is, because I have a two tank system (conventional septic tank and an effluent pump tank) how is the effluent tank vented? I do have two roof vents and the original install back in 1996 never had a yard vent and I'd assume the concrete riser lid I just replaced was fairly well sealed before the lids frame cracked and separated... so that makes me feel a little better.

However, I know while replacing the pump and installing the PolyLok riser, that tank had a good bit of heat inside of it... so the gas is there. Last thing I want is to walk away from this thinking I made a nice upgrade with the sealed PolyLok riser and lid and then in a few weeks I end up with a backup in my house because the tank isn't able to vent itself.
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