Backflow / Backwater valve

I had a question regarding the placement of a backflow valve. I am in a rural area with a 1000 gal septic tank and lateral lines. My problem is that during times of heavy or prolonged rain my drainage field becomes saturated. This saturation results in water being sent back from the lateral lines to the septic tank eventually filling the tank. My question is this: Could a backflow valve be installed between the junction box and the septic tank? Everything I have seen online shows these valves being installed between the septic tank and house. My thought process for putting the valve between the tank and junction box is that during these heavy rain periods we could still use our septic tank.

I can't think of a reason why not?

Well, if I'm understanding what you want to do, it would stop water from filling up the tank and potentially coming into the house. So during the heavy rainfall when you know your field is saturated, you will have to limit your water usage

The potential problem I see with your placement would be that the flow into a septic tank, as well as the outlet , is typically almost level and will not have very good flow velocity. The backwater valve may create too much of a restriction and eventually booger up with film and clog.

You could go with a pump and check valve. I would be cautious of using a check valve on a gravity system though.

I have exactly the same issue as squishy.

I have 2 500 gallon tanks for a total of 1000 gallons. The setup is about 9 years old now. We have received about 8 inches of rain in less than 36 hours at my house. Mostly in heavy burst down pours like 2 inches in 20 min. So we have been flash flooding several time a day for days now. It is not coming in the house but the septic tank is filling up with flood water. When it is flooding the water is 6-12 inches deep over the top of the lateral line field & deeper in other areas. when the water goes down the tank drains back down to normal level in no time. (I kind of wonder if this has anything to do with the 5 million gopher holes on my property, but that another issue) The only good fix I have been able to think of is to put a backflow valve on the outlet from the tanks. If anyone has another idea or hopefully a better idea then PLEASE speak up!!!!

Squishy & I will surely appreciate any helpful input.

I can't help but think you are mocking me with your username