Septic System Regulations in Delaware

In Delaware, onsite wastewater (septic) systems are regulated by Delaware Department of Natural Resources and Environmental Control (DNREC), Division of Water — Groundwater Discharges Section (on-site wastewater / septic program), which issues onsite wastewater permits directly. Installing, replacing or repairing a septic system here means, in sequence: a site and soil evaluation, a design, a permit application, an inspection while the system is open, and a final as-built record once it is approved.

Who regulates septic systems in Delaware

The state-level regulator is Delaware Department of Natural Resources and Environmental Control (DNREC), Division of Water — Groundwater Discharges Section (on-site wastewater / septic program) (official program page). DNREC's Division of Water, through its Groundwater Discharges Section, directly reviews and approves site evaluations, issues design permits, and licenses the private-sector professionals who evaluate, design, and install systems. There is no county or local health department permitting role; DNREC's homeowner guide describes a three-step state process (site evaluation, design/permit, licensed installer).

The statewide onsite-wastewater code is cited as 7 DE Admin. Code 7101, "Regulations Governing the Design, Installation and Operation of On-Site Wastewater Treatment and Disposal Systems" (under 7 Del. C. ch. 60). We link the agency's own page above rather than restating specific numeric requirements from it, since those change by rule revision and by local amendment.

The permit sequence

The order of operations is broadly consistent across the country, even though the specific numbers in each step vary by state and often by county. None of the figures below are specific to Delaware; treat this as the shape of the process, and get the actual numbers from the agency linked above or from the county office.

1. Site and soil evaluation. A qualified evaluator (see licensing below) digs test pits or runs a percolation test, and records the soil profile, depth to seasonal water table, depth to any restrictive layer, and slope. This determines whether the lot can support a conventional system or needs an alternative design.
2. Design. Under most state codes, daily design flow is set from bedroom count, not square footage. That flow drives tank capacity, and the soil evaluation sets the drainfield application rate and therefore its size. The designer also lays out setbacks to wells, property lines, surface water, foundations and a reserve/replacement area.
3. Permit application. Submitted to whichever office issues permits here (state agency or county/district health office, per the delegation model above), along with the design and soil work.
4. Installation and open inspection. The installer builds the system, and it is inspected before backfill while it is still open to view.
5. As-built and approval. A final drawing of what was actually built is filed once the system is approved. That as-built is the document a future owner, pumper or inspector needs, and it is what ends up in the county record.

Who can design and install a septic system

Getting septic records in Delaware

Septic records in Delaware are generally held by the county or local health jurisdiction that issued the permit, not by the state agency, and are released under the state's public records law. We have not logged the specific statute name and response deadline for Delaware yet; check with the county office listed on its records page below, or with Delaware Department of Natural Resources and Environmental Control (DNREC), Division of Water — Groundwater Discharges Section (on-site wastewater / septic program).

Counties in Delaware we hold records for

We hold 22,040 septic records across 3 of 3 Delaware counties. Each county page below shows exactly where its records are kept and how many we hold.

Full Delaware county-by-county index · Open the parcel map

Common questions

Who regulates septic systems in Delaware?

Delaware Department of Natural Resources and Environmental Control (DNREC), Division of Water — Groundwater Discharges Section (on-site wastewater / septic program). DNREC's Division of Water, through its Groundwater Discharges Section, directly reviews and approves site evaluations, issues design permits, and licenses the private-sector professionals who evaluate, design, and install systems. There is no county or local health department permitting role; DNREC's homeowner guide describes a three-step state process (site evaluation, design/permit, licensed installer).

What is the septic permit process in Delaware?

The sequence is a site and soil evaluation, a design sized from the evaluation and (under most state codes) bedroom count, a permit application, an inspection before backfill, and a final as-built filed once the system is approved. Exact numeric requirements are set by the agency's own code, not restated here.

Who can install a septic system in Delaware?

DNREC-licensed Class E system contractor (installer). Class F liquid-waste haulers pump tanks; Class E or Class H inspectors handle failure inspections. https://dnrec.delaware.gov/water/groundwater/septic-systems/

How do I get septic records for a property in Delaware?

Septic records are generally held by the county or district health office that issued the permit. See our county-by-county Delaware index for the specific office and portal in each county.

Sources

• https://dnrec.delaware.gov/water/groundwater/septic-systems/
• https://documents.dnrec.delaware.gov/Water/Septics/Simply-Septics.pdf
• https://regulations.delaware.gov/AdminCode/title7/7101

Regulatory information on this page was researched against official state agency sources and last verified 2026-08-31. It is informational only: the agency linked above is authoritative, and requirements can change. We are not lawyers, not a government body, and not affiliated with, licensed or certified by any agency named on this page.