How deep should drainfield be?

[bordercollie050]

Hello everyone!

I'm getting closer to installing my septic system and with my tank placement (approx 200ft from house) I'm at 20" deep on my drainfield lines. I had a few septic people over to bid on the job and they think that's too deep??? (code says up to 36") (bids came in around 7-9k for 1500gal tank and 300' of leach line)

Also, the area is a bit on the saturated side but does genly slope downhill (about 1" of hill every 5 ft). And I have access to a road ditch running parallel (so I could run field tile and futher drain this area off) BUT at the moment, any hole deeper than 3 ft fills with ground water (to the 3ft line) and there is A LOT of clay (I know, bad situation)

I would like to use a gravelless system but gravel is so cheap here and I dont really trust the "drain tile pipe" wrapped in foam chips - standard gravelless (i.e. if some clown drive over my field it seems they would get damaged vs schedule 40 PVC

 

[Smooky]

In NC the county environmental health inspector/sanitarian determines the size, location and depth of the septic system. Here is an Iowa link. You may want to contact your local sanitarian:

http://www.iowadnr.gov/Environmental-Protection/Water-Quality/Private-Septic-Systems

 

[Sponsor]

 

[bordercollie050]

In NC the county environmental health inspector/sanitarian determines the size, location and depth of the septic system. Here is an Iowa link. You may want to contact your local sanitarian:

http://www.iowadnr.gov/Environmental-Protection/Water-Quality/Private-Septic-Systems

I have a permit, and the "county" okayed 20" (state law up to 36").

I know some states have a saturation test (fill a hole with water). my holes drain but I can see where closer to surface would be better (everyone says these things dont freeze).

Anyhow, I will probably bring in some sand b/c it's cheap and run drain tile along the property line to a ditch

 

[Smooky]

If the county said 20" , They probably mean no deeper than 20 inches. If water is standing in the hole at 36 inches it sounds like you have a wetness problem. I would not install it any deeper than what they said. You might want to go ultra shallow so that the bottom of the trench is about 12 inches deep and you bring in soil to cover it up. If you change anything I would call and get their blessing first. Most come out and do an inspection before it is covered up. If it ain't like they said do it, they might make you dig it up and do it again. Could get expensive.