SEPTIC TANK INSTALLATION DEPTH

[Jazzman]

Hey, can anyone tell me what the code is for setting a septic tank. I’m replacing an old steel tank with a code approved 1,000 gallon norwesco tank. There’s a layer of bedrock at about 48” so I’m not sure how much I will need to jackhammer to get tank installed properly. You can buy a riser as short as 6” high so that suggests that 6” of cover is minimum required. I’m located in central Oregon.

Thanks!

 

[Reach4]

No relevant experience... I think if there were a fixed depth minimum for the top of the tank, it would be mentioned here:
https://www.clackamas.us/septic/guideseptictankreplace.html says

Bedding material (for example, pea gravel) is placed in the bottom of the excavation to provide a stable leveling base. The tank must be placed level from side-to-side and end-to-end. The depth of excavation must be determined before setting the tank to insure that the building sewer pipe can maintain the minimum/maximum grade set by the plumbing code once it is connected to the tank inlet fitting.
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Farther down in the document, the "Septic tank placemement [sic] for systems that were built before July of 1977" section talks of what you can do if replacing an old installation that does not conform to the newest regs.

 

[Sponsor]

 

[LLigetfa]

Unless you have a sewage pump, the tank depth would be determined by the height of the inlet and the outlet.

 

[Jazzman]

Thanks for all of your input!