Douglas County requires a septic Use Permit when a property sells or changes ownership — but that program is about the wastewater system, and no well water test appears anywhere in it. For a Douglas County well property, testing at sale is the buyer's lender's call, alongside the free statewide DWR ownership filing every well sale needs.

County requirement	No well-water test appears in the county's Use Permit program — the permit required at sale or change of ownership covers the septic system (with time-stamped photo documentation since December 2023).
What usually drives testing	The buyer's lender. Government-backed loans commonly require water quality evidence for homes on private wells.
Statewide filing	Every Colorado well sale needs the free DWR change-of-owner filing so the well permit follows the property. source ↗
County contact	Douglas County Health Department, 720-643-2400.

Details to confirm with the county

We couldn't confirm the following from Douglas County's official pages. Check these with the county before you rely on them:

• Whether Environmental Health ever asks for a water sample under the Use Permit's 'other reasons deemed necessary' clause — the published program doesn't mention one.

Verified July 2026 · Source: Douglas County Health Department — Use Permits (Septic Systems)