Buying Land in Delaware: The State Framework Behind Every County

Only three counties -- and each one genuinely zones

Delaware has just three counties -- New Castle, Kent, and Sussex, from north to south -- which means a single county government covers far more of the state's land area, and a far larger share of its unincorporated land, than a typical county does elsewhere. All three hold real zoning authority over their unincorporated territory: New Castle County administers zoning through its Unified Development Code and Department of Land Use; Kent County through its Department of Planning Services under the Levy Court; and Sussex County through a Planning & Zoning Commission and County Council that administer the county's zoning ordinance. Incorporated towns and cities within any of the three counties generally zone themselves, separately from the county.

In practice that means the county-versus-municipality question that trips up buyers in some states is simpler here: for unincorporated land, the county planning or zoning office is the right first call in all three counties, with no separate parallel town layer to worry about unless the parcel sits inside an incorporated municipality's limits.

The Coastal Zone Act: a ban on new heavy industry, not a buffer or density overlay

Delaware's coastal protection law works on a fundamentally different mechanism than Maryland's Chesapeake Bay Critical Area Act next door, and the two should not be treated as equivalents. The Delaware Coastal Zone Act, enacted in 1971 and codified at Title 7, Chapter 70 of the Delaware Code, does not create a graduated buffer or density system based on distance from water. Instead, within a mapped coastal zone running along Delaware's Bay and Atlantic coastline, it flatly prohibits the construction of any new heavy industry use that was not already operating on June 28, 1971 -- no permit can be issued for one, period. A narrow "conversion permit" track lets the state allow an alternative heavy industry use at a site that already had a qualifying heavy industry use (or an existing dock or pier serving one) as of that 1971 date, but that exception does not open the door to new heavy industry on undeveloped coastal land.

Other manufacturing uses inside the coastal zone are not banned outright the way heavy industry is, but they do require a standard Coastal Zone Permit from the Department of Natural Resources and Environmental Control (DNREC) before construction or expansion, and bulk product transfer facilities are generally prohibited except through that same narrow conversion-permit path.

For most land buyers -- anyone looking at residential, agricultural, or ordinary commercial use -- the Coastal Zone Act simply will not come into play, since it targets a specific category of industrial and bulk-transfer use rather than imposing a general buffer or setback on all development the way Maryland's Critical Area buffer does. Where it matters is for a parcel inside the mapped coastal zone that a buyer intends for manufacturing, heavy industry, or bulk transfer use -- that combination requires a DNREC Coastal Zone Act determination before assuming any development plan is workable, regardless of what county zoning allows.

Wetlands: state permitting for tidal wetlands, plus a county zoning sign-off

Delaware's Wetlands Act, Title 7, Chapter 66 of the Delaware Code (enacted 1973), requires a DNREC permit for most activity in a regulated wetland -- and the statute specifically regulates all of Delaware's tidal wetlands, plus non-tidal wetlands only where a contiguous non-tidal wetland area reaches 400 acres or more. Most of Delaware's smaller non-tidal wetlands fall outside this state permit program and are addressed instead through federal Clean Water Act Section 404 jurisdiction (administered by the U.S. Army Corps of Engineers) rather than a state wetlands permit -- a distinction worth confirming for any specific parcel rather than assuming DNREC's wetlands permit is the only wetlands review in play. Notably, the Wetlands Act also requires that the county or municipality with zoning jurisdiction over the site approve the proposed activity before DNREC can issue its own permit -- the state and local processes run in sequence, not independently.

Inland Bays and Chesapeake watershed nutrient programs

Separately from the Coastal Zone Act and Wetlands Act, DNREC administers watershed-specific pollution control strategies under Delaware's Water Pollution Control Law (Title 7, Chapter 60), including nutrient total maximum daily loads (TMDLs) and a Pollution Control Strategy for the Inland Bays watershed -- Rehoboth Bay, Indian River Bay, and Little Assawoman Bay -- addressing nitrogen and phosphorus loading tied to algal blooms and low dissolved oxygen in those waters. A small slice of northern Delaware (parts of New Castle and Kent counties) also falls within the Chesapeake Bay watershed and is covered by Delaware's piece of the multistate Chesapeake Bay Watershed Implementation Plan. These are water-quality programs aimed primarily at agricultural and stormwater nutrient sources rather than parcel-level zoning restrictions, but they can affect nutrient management requirements for a given property.

Septic: regulated directly by DNREC, statewide -- not delegated to local health departments

This is a genuine structural difference from Maryland (and Virginia): Delaware septic systems -- termed on-site wastewater treatment and disposal systems -- are regulated directly by DNREC statewide under 7 DE Admin. Code 7101, not delegated out to county health departments as an Approving Authority. DNREC itself licenses the percolation testers, site evaluators, system designers, installers, and inspectors, and directly reviews and permits systems under 2,500 gallons per day (small systems), which covers essentially all single-family residential septic systems. An approved site evaluation is generally valid for five years from DNREC's approval date.

For a buyer, this means there is one statewide agency to call about septic feasibility on any Delaware parcel, in any of the three counties -- DNREC -- rather than a different local health department depending on where the parcel sits. County government still separately controls the zoning and subdivision approval the lot needs before a septic permit becomes relevant, so both processes apply, just through different agencies.

What this page does not tell you

Everything above is the state-level layer. Specific zoning district rules, minimum lot size, and setback requirements are each county's own (or, inside a municipality, that town's own) and are not standardized across Delaware's three counties. See our national guides to zoning, septic systems, perc tests, and wetlands for the general process once you have a specific county and parcel in mind.