Highway Surface Water Entering Septic Tank

[Lilads]

I live on a newish estate of 8 house which we share a septic tank. Over the last few months we have spent lots of money having to have tankers empty it. We believe surface water from the highway which runs from further up on the road surface then runs onto the verge and drains into the ground the other side of the fence to where our tank is and we think it is entering our septic tank and overwhelming it. We have spoken to the highways and they will try to stop the water running down the round but it is not currently a top priority for them. Is there any action we can take against them as their water is flooding our tank or is it our responsibility? If you have any links with info I would be very grateful..

Thank you

[The Builder]

I know this may be a silly question Lilads, but are you sure it is being filled by surface water?

Septic tanks work by being full all the time (effluent from the houses.) The soakaway outlet is at the top of the tank. It doesn't overflow until full. Solids are left at the bottom. When a tank is "emptied", it is really being de-sludged. Obviously the water is removed as well, but it's the sludge that they're after.

Also, tanks have a cover, and an inspection chamber just before the inlet. Only a flood could allow surface water to get in through the cover. There should be no other way in to a septic tank.

[Lilads]

Thanks for your help. I'm not sure if this is the cause to be honest but the road has no drainage and it collects on the verge next to our fence near our tank, it looks like there was a roadside ditch that was never maintained and so as it soaks into the ground the tank overflows. I believe the water table must still be fairly high due to the heavy rain we have been having.