How to find groundwater intrusion into Septic Tank

Igotadose

We have an EnviroCare P6 tank, installed in 2004 in our yard. It seems that there is water getting into the tank when we're not using any of the fixtures (toilets, showers) aren't used. We believe it's groundwater intrusion, there are no obvious leaks, the lid is sound, we get the tank pumped regularly and its BioCycle serviced.

How do you find out where the water might be coming from? Are there well-known weak spots for this tank?

FWIW the water table in our area is high, yard is soaked after a heavy rain with standing puddles.

Thank you

upupup

Igotadose wrote: »

We have an EnviroCare P6 tank, installed in 2004 in our yard. It seems that there is water getting into the tank when we're not using any of the fixtures (toilets, showers) aren't used. We believe it's groundwater intrusion, there are no obvious leaks, the lid is sound, we get the tank pumped regularly and its BioCycle serviced.

How do you find out where the water might be coming from? Are there well-known weak spots for this tank?

FWIW the water table in our area is high, yard is soaked after a heavy rain with standing puddles.

Thank you

Check all the inspection chambers during the heaviest showers.
It could also be water coming back from the percolation area if that area is saturated

Igotadose

upupup wrote: »

Check all the inspection chambers during the heaviest showers.
It could also be water coming back from the percolation area if that area is saturated

Tank has an Ebara pump that pumps the effluent to a remote distribution box. So, there's no possibility of inflow from the percolation area.

Fwiw it seems that even without rain there's influx, but slower.

Any ideas where the vulnerability points might be in the tank?

Igotadose

Sorry, what are the inspection chambers? Thanks.

upupup

Igotadose wrote: »

Sorry, what are the inspection chambers? Thanks.

A manhole which is between your house and the tank,used for rodding blockages.Rain may be getting during heaving showers

Igotadose

upupup wrote: »

A manhole which is between your house and the tank,used for rodding blockages.Rain may be getting during heaving showers

There isn't one. The house, built in 2004, is surrounded by a concrete footpath. The septic flow from the toilets goes through orange piping sunk into the concrete. At various points in the footpath (the corners chiefly), there are lids you can pry up and watch things flow by. All the wastewater flow goes out to the tank from one point, the southwest corner of the footpath.

Between that point (which has a lid), it's about 10 meters to the input of the septic tank. There's no manhole or other access between that point and the tank. It's fairly flat, and runs under the driveway. My guess is it drops down about a meter eventually from that southwest corner to the septic tank input.

I don't think the rainwater is getting into the septic pipe access points. In fact, the water level in the tank rises even when it doesn't rain. Could the water be making its way into the pipe that runs from the southwest corner, to the tank? Is there some way to tell, like get a camera run down that pipe? We had a crew out looking at the percolation field with a camera and they could take videos of that pipe, I'm thinking of contacting them to see if they can video the input if the southwest-corner outflow pipe. There's no smell or anything, it all actually runs perfectly well, its just concerning the tank is filling without use. If we get a prolonged power outage, the pump will not run and empty the tank and that would be a scary situation!

Thanks again.

upupup

Igotadose wrote: »

There isn't one. The house, built in 2004, is surrounded by a concrete footpath. The septic flow from the toilets goes through orange piping sunk into the concrete. At various points in the footpath (the corners chiefly), there are lids you can pry up and watch things flow by. All the wastewater flow goes out to the tank from one point, the southwest corner of the footpath.

Between that point (which has a lid), it's about 10 meters to the input of the septic tank. There's no manhole or other access between that point and the tank. It's fairly flat, and runs under the driveway. My guess is it drops down about a meter eventually from that southwest corner to the septic tank input.

I don't think the rainwater is getting into the septic pipe access points. In fact, the water level in the tank rises even when it doesn't rain. Could the water be making its way into the pipe that runs from the southwest corner, to the tank? Is there some way to tell, like get a camera run down that pipe? We had a crew out looking at the percolation field with a camera and they could take videos of that pipe, I'm thinking of contacting them to see if they can video the input if the southwest-corner outflow pipe. There's no smell or anything, it all actually runs perfectly well, its just concerning the tank is filling without use. If we get a prolonged power outage, the pump will not run and empty the tank and that would be a scary situation!

Thanks again.

The lids that you can pry up are the inspection chambers/manhole.If you're confident that no rain in getting in here then putting a camera down the pipe is a good idea to look for problems.

shane b

You could possibly also use Drain tracing dye to see if it shows up anything.

I have a similiar issue with our concrete tank. We are getting soakage from the surrounding drive/garden area and the water is seeping along the pipework and seeping into the inlet pipes via the inlet inspection ports where the top half of the pipe is open. The riser on these inlet ports are built with cavity block which doesnt help with keeping the water out. We were advised precast risers and proper AJs would help a lot but the paths and drive round the house was done when we bought the house so it would be a big enough job, so we have lived with it.

Igotadose

upupup wrote: »

The lids that you can pry up are the inspection chambers/manhole.If you're confident that no rain in getting in here then putting a camera down the pipe is a good idea to look for problems.

Thanks again. Is there a 'common name' for the pipe that runs from the house, to the septic tank? Feed pipe/Input pipe/"The pipe that runs from the house to the septic tank?"

markjbloggs

Igotadose wrote: »

Tank has an Ebara pump that pumps the effluent to a remote distribution box. So, there's no possibility of inflow from the percolation area.

Fwiw it seems that even without rain there's influx, but slower.

Any ideas where the vulnerability points might be in the tank?

Does the pump have a check valve? If so, is it working properly. Is the percolation area saturated?

Igotadose

markjbloggs wrote: »

Does the pump have a check valve? If so, is it working properly. Is the percolation area saturated?

Pump doesn't have a check valve. It pumps to an elevated percolation area, into a distribution box where the input to the box is near the top, and the percolation pipes at the bottom.

And the percolation area isn't saturated. It's fairly dry pretty much year round

upupup

Igotadose wrote: »

Thanks again. Is there a 'common name' for the pipe that runs from the house, to the septic tank? Feed pipe/Input pipe/"The pipe that runs from the house to the septic tank?"

The pipe that runs from the house to the septic tank is usually called the pipe that runs from the house to the septic tank:D

How much extra water do you think is getting in and how much time does it take to fill when it happens?

Igotadose

upupup wrote: »

The pipe that runs from the house to the septic tank is usually called the pipe that runs from the house to the septic tank:D

How much extra water do you think is getting in and how much time does it take to fill when it happens?

Last week, the alarm went off Thursday early a.m.. It had rained fairly heavily overnight and the pump had not kicked in (float problem as it turned out.) That yielded easily 8 inches over the normal level. Through yesterday, heavy rain would raise it sometimes a foot, maybe 2 over normal when the pump was turned off.

On nights that it didn't rain, it was still around 6-8" over normal. These are approximate from my memory of course, didn't record how far above normal.

We don't add a lot of water to the system. Just two people in the house, no dishwasher, 2 showers a day, low-flow fixtures. The clothes washer does not go to the septic, only toilets and the shower go to the septic. All the other sinks go to the various soakaways.


The pump was reactivated after the float problem was resolved yesterday, things are fine despite rain yet again.

upupup

take a look at the water tanks in the attic,they may be overflowing into the system