Backwater valve on drainfield

damian51

My septic drainfield has an overflow pipe that goes into a ditch. Under heavy rain the ditch can fill above the pipe. Should I install an backwater valve on the end?

Daniel Holzman

This is totally unique. Septic fields are not generally designed to overflow onto the ground, that is exactly the opposite of how they are intended to operate. Are you absolutely certain the "overflow" pipe you refer to is in fact an overflow from the septic system? And if the ditch can get higher than the overflow pipe, this suggests that under those conditions, your septic system is in fact below the water table, which is another serious problem, as the bottom of a septic system is typically designed to be at least 4 feet above the high water table.

From your description, possibly you have an old, unapproved, undesigned system, which sounds like it has serious issues that are not going to get solved by installing a backflow preventer.

joecaption

I agree 100% on this one. I have lived most of my life in the country, helped my dad install our own septic tank 35 years ago, and used to work for a company that installed septic tanks and have had to have dozens of new tanks installed on propertys I'm working on and never once have I seen an over flow.
Sounds like someone added one because the old leach field was failing.
Time to call in some septic tank pro's on this one.
Someone finds out about this and complains your going to be in far more do do then you are now.

damian51

Maybe I got my information crossed.

It's a new septic system, passed inspection and all that...new house. It definately has something to do with the leech field, not sure if it's actually connected....might be a curtain drain to drain the field during really heavy rainfall?


And the pipe only gets covered during extremely heavy rainfall periods...then the ditch drains and all is well.

It has to be something legit cause it passed inspection and all the houses here have it.

joecaption

Can not imagine any county allowing raw sewerage to be dumped into a ditch.

damian51

I'm not too sure what it is, but every house has it and some have the backwater valve, some dont

damian51

Finally got around to pulling the final approved permit on the septic. Under type it says "ATU with ER"

I'm pretty sure atu means anaerobic treatment unit....what does ER mean?

I guess it has something to do with the field lines, it says 100' of E/R field lines


Anyone give me more info?

joecaption

Why not just call the company that installed it and ask them how it works?

Daniel Holzman

This makes a little more sense. ATU is a special type of system that replaces a septic tank with an anaerobic digester, usually equipped with a pump. This is usually used to reduce the nitrate concentration entering the water supply. I am guessing the ER is effluent return, which is a common technique used to recycle a portion of the effluent which would otherwise go to the leaching field. But you really should have plans for the system, else get them from the Town, or perhaps from the installer. These systems can be complex, and may require special maintenance. As to modifying the system by installing a backflow preventer, that is an issue for the designer and installer of the system, and perhaps the Town that issued the septic permit.

damian51

Called the installer, he said he will send me some info.


Also found out it uses an hancor arc-24 leech field....any reviews on it?