Diligence · Glossary
Percolation Test
Updated 2026-07-20
A percolation (perc) test measures how quickly soil absorbs water and is commonly required for septic suitability. SSURGO soils are a screen—not a perc result.
What it means
A percolation (perc) test measures how quickly soil absorbs water and is commonly required for septic suitability. SSURGO soils are a screen—not a perc result.
Why it matters for land decisions
Confirm how the concept applies to your specific parcel with the city or county planning department and the controlling agency map or ordinance.
- Treat online GIS as a first-pass screen.
- Verify before design, escrow, or lending decisions.
People also ask
What is Percolation Test?
A percolation (perc) test measures how quickly soil absorbs water and is commonly required for septic suitability. SSURGO soils are a screen—not a perc result.
Is a GIS overlay enough to decide?
No. Public GIS is a screening tool. Official determinations come from the governing agency, recorded documents, and licensed professionals when required.
Official sources
Related terms
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Parcel View screens zoning, flood, fire, soils, and planning layers for any California lot — every finding linked to the official source.