Summit County is the clearest seasonal-window case: OWTS permits generally cannot be issued October through May, because freezing and snow prevent the required site work. Environmental Health must visit the property to verify soils, groundwater, and setbacks — and groundwater not checked in the seasonally high period may be conservatively assumed shallow, driving the design.

The season	OWTS permits generally cannot be issued October–May — the practical testing and permitting window is roughly June through September. Plan land closings and build schedules around it.
County site visit	Environmental Health staff must visit the property and verify that soils and groundwater conditions are suitable and that setbacks can be met before a design is permitted.
Groundwater timing	If groundwater isn't checked during the seasonally high period, the county may conservatively assume shallow groundwater and require an OWTS design appropriate for it — which usually costs more.

Details to confirm with the county

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

• Exceptions the county grants within the October–May pause (the FAQ says 'generally').
• Current evaluation and permit fees.

Verified July 2026 · Source: Summit County — OWTS FAQ (permit season and site verification)