Soils Investigations for On-lot Septic Disposal Systems
Parker Consults has been working with sewage enforcement officers and PA DEP throughout Western Pennsylvania on soil suitability for on-lot disposal systems.
PA Act 26 – Alternative On-Lot Disposal System Technology:
Pennsylvan
ia Department of Environmental Protection allows for alternative on-lot septic systems when “conventional” systems cannot be approved. This is generally when soils have a limiting layer of less than twenty inches. Limiting layers include seasonally high water tables (hydrologic) or rock (lithic).
These alternative systems generally involve a combination of specific approved alternative treatment system and alternative disposal system. A summary of the PA DEP Approved Systems can be found at: https://www.dep.pa.gov/Business/Water/CleanWater/WastewaterMgmt/Act537/OnlotDisposal/Pages/OnlotAlternateTechnologyListings.aspx
These systems are generally designed by certified designers.
Alternative systems (where there is less than 20 inches to limiting layer) requiring a professional soil scientist are described in the above link.
PA Act 26 Subdivision Planning – Planning Module Component 2 for new land development.
There are some additional requirements for sub-developments relative to soil investigations for Alternative Disposal Systems. These are:
- A primary and a secondary disposal area that meets the alternative system soil and slope criteria.
- A secondary disposal system for the existing residence if there is an existing residence on the property that is going to be subdivided.
- Mapping of all soil test pits and the proposed primary and secondary disposal areas.