Strange drainage issue

Hi there

bit of an odd one that somebody may be able to help with.

I have a septic tank and noticed that it was filling with liquid quicker than usual. I’ve taken a look and noticed that there is a constant stream of water entering it through one of the inlets. Problem is, I’m not sure where the water is coming from as it is happening when we are not using water. I’ve check the manholes and cannot see water flowing through any of them. I’ve even turned off the water in the road for 60mins to rule out any rogue overflow, but the constant stream continues.

I’ve been checking it when it isn’t raining to rule out rainwater going into the system (I believe the rainwater isn’t connected to the drains going to the tank anyway).

Any ideas why it could be? My only idea at the moment is that there is a crack on the drain run after the manholes and that is allowing water from the recent rain we’ve had to leak into the pipe and then into the tank.

Thanks in advance for any help. Either way, I think I’m going to need a CCTV survey to work out the source of the water.

Your ground would have to be seriously saturated to provide such a flow.....I suppose no one else is connected to your tank?
Nothing hugely to worry about so long as the outfall is coping, and hopefully dryer weather will eventually come our way!
John

Dig it up just enough to see in which direction it is aiming but can't see it being rain water.

Single dwelling septic systems usually have one inlet. You say it's filling faster than usual, have you recently had it emptied to notice this because the first holding chamber should be full to work properly

Burnerman said:

flow.....I suppose no one else is connected to your tank?

Click to expand...

If there is there ought to be something in the deeds to that effect?

I don’t think there is anybody else connected to the system and it wasn’t in the deeds. But the flow of the water into the tank looks like there could be another connection.

I can tell it’s filling quicker than usual because the level is frequently high enough for the pump to kick in and get rid of the water. It is running even in the morning when no water has been put into the tank for 10 hours or so. What I’ve found it what when the pump has run longer enough to get the liquid level down, it quickly rises up again even when no water is running from the house.

Just to be clear, it’s an onion type septic tank with a pump to get the water out and into the drain field.

Thanks again for the replies.

If your on a septic tank there could be land drains in the area, if you have a crack or open joint between your last manhole (with no water showing) and the tank it could be letting on ground water.

Really needs a CCTV, your home insurance might cover the costs of any investigation work and repairs.

Thanks Ian H. I was thinking the same as you. I have called the insurance company and they are sending someone out to diagnose the problem. It must be something between the last manhole and the tank because I see no water running through the last manhole but can hear water flowing further down the pipe!

One concern I have is that we have the tank emptied recently (do this annually), and because of the really wet conditions over the last few months the weight of the wet soil could have shifted the tank. Thankfully it looks like that is covered by my policy.

Anyway, I’ll see what the drainage firm says.

thanks again

Common issue, especially with clay soils, is a high water table, and given recent rainfall levels, the ground is pretty saturated in a lot of areas. My money is on you've a break in the pipework, and its allowing groundwater into the system. Used to empty a lot of septic tanks around the Northants and Cambs area a few years ago, a fair few were refilling from the outfall as the tanker was drawing the effluent out.

Also quite possible the tank has shifted, if the ground is waterlogged and the tank emptied, they've been known to 'pop up' out the ground, with the pressure of the groundwater, only solution to that is to concrete the tank in....