# Increase grade above septic/leach field?



## LawnInAK

I live in a new construction house that was fairly poorly graded. On one side of the house, I added a good amount of dirt to improve grade and seeded a lawn. I'm getting ready to tackle the other side where the septic system is. 
Some of my neighbors (also new construction) bit the bullet and paid landscaping companies for hydroseed. I've noticed that the landscapers added a good amount of dirt (in a couple cases what looks like a couple feet) on top of the septic before seeding. I'm assuming to ensure that rain/snow doesn't pool on top.
All of the sources I'm finding on the internet about landscaping over a septic says not to add any dirt over it before seeding grass.
What should I do here? Thank you!


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## ken-n-nancy

LawnInAK said:


> ... I'm getting ready to tackle the other side where the septic system is.
> Some of my neighbors (also new construction) bit the bullet and paid landscaping companies for hydroseed. I've noticed that the landscapers added a good amount of dirt (in a couple cases what looks like a couple feet) on top of the septic before seeding. I'm assuming to ensure that rain/snow doesn't pool on top.
> All of the sources I'm finding on the internet about landscaping over a septic says not to add any dirt over it before seeding grass.
> What should I do here? Thank you!


I'd suggest getting the septic plan for your system from your local municipality. I don't know about Alaska, but in New Hampshire, the town keeps septic plans on file for all systems. I can't imagine Alaska would be different in that regard, but I don't have direct experience to know. (I haven't lived in Alaska since I was 4 years old...) Your local municipality probably also has a code inspector on site that can probably answer some questions for you.

Septic systems are generally planned to have anywhere from 6 inches to 30 inches of soil on top of them. However, not all septic systems are the same; depending upon the type of system you have installed and how deep the current topsoil is above the septic field, you may be able to add a couple feet of soil without issues, or you may only be able to add a few inches more. (Note however, that operating heavy machinery over the septic field is NOT a good idea. A small riding mower would be fine, but a tractor or a bobcat skid steer can be heavy enough to crush pipes, distribution boxes, etc. The spreading of the topsoil over the septic field should be done without heavy equipment. (A wheelbarrow, shovel, and rake are probably the preferred tools...) However, it is also possible that more than about 6" of topsoil could cause problems.

In general, from what I have read and investigated when renovating the lawn over our septic field, I found that "just adding topsoil is generally OK if it isn't more than a couple of inches." (See this EPA publication.)

Personally, I would seek to find out how much topsoil was supposed to be over your drain field (aka "leach field"), check to see how much is actually there, and add more if you don't already have at least 8" over the sand / rock of the drain field.

If doing any regrading near a septic field, you want to ensure that grading doesn't divert rain water or snow melt onto the septic field and that there is no "ponding" on the septic field.


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## LawnInAK

Perfect thanks so much!


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