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Population: 783,600

Information on the state of Delaware is available for the following topics. To review this information, click on the links below.

Contacts| Regulations, Statutes & State Codes | Quick Facts | Septic Stats

Onsite Demonstration Programs | Onsite Management Communities



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Rodney Wyatt, Program Manager, or
John G. Hayes, Jr., Environmental Scientist
Department of Natural Resources and
Environmental Control - GWDS
Division of Water Resources
89 Kings Highway
Dover, Delaware 19901
(302) 739-4762, or (302) 739-4761 (respectively)
(302) 739-7764 (fax)




Regulations, Statutes & State Codes:
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Delaware State Regulations

Delaware Constitutions, Statutes and Codes

All sections of Delaware onsite regulations are currently under revision; the effective date is uncertain at this time, but is expected to be April 1, 2002.

In Delaware, conventional, experimental, and alternative technologies are permitted by regulation. Other technologies may be allowed by providing either NSF ratings or years of experience of usage and area utilized. Surface discharge for onsite systems is not an option in Delaware.

State Code allows for drainfield area/size reductions, based on advanced treatment, gravelless chambers, and/or low flow fixtures. Aerobic treatment units (ATUs), gravelless chambers, and low flow fixtures are technologies considered for drainfield area/size reductions.

Funding programs or mechanisms exist to assist homeowners replacing failing systems or installing new systems through the State Revolving Fund (SRF). Questions should be directed to:

Brian Motyl
Housing Mortgage Loan Officer
Financial Assistance Branch, DNREC
5 East Reed St.
Dover, DE 19904
(302) 739-5081 (phone)
(302) 739-2137 (fax)

For information about onsite wastewater demonstration, research, or testing projects, contact:

Jack Hayes, Environmental Engineer IV, at the address above or phone (302) 739-4761, fax to (302) 739-7764, or email to jhayes@state.de.us

Delaware Code recognizes or requires management programs/contracts or management districts to monitor and maintain large systems greater than 2,500 gpd (requires an operator), but does not require such programs/contracts for individual small systems; however, permits require pump-out of septic tanks once every three (3) years. Local agencies do not have authority to adopt or require maintenance/management programs. The number of permits issued per year is tracked by the State for new construction and for repair or replacement of existing systems; records are maintained at the State level.

A failed system is defined in Delaware as one that no longer accepts wastewater, where there is overland flow of wastewater, and/or one that provides inadequate treatment of wastewater (cesspools/seepage pits). The most common reasons for system failure in the State include poor system siting, poor construction/installation, poor soils work/inaccurate interpretations, and/or poor maintenance (pumping and operation, never serviced).

The State offers a licensing/certification program for onsite wastewater professionals. In Delaware, private professionals engineers are licensed to conduct an engineered construction inspection or private site evaluation. A new licensee, a Class H System Inspector, is proposed in the Regulation revisions.

Information pertinent to municipal wastewater regulations may be obtained from R. Peder Hansen at the address above, by calling (302) 739-5731,or by emailing rhansen@state.de.us.

For spray irrigation information, Ron Graeber, Program Manager, may be contacted at the address above, by phoning (302) 739-4762, or by emailing rgraeber@state.de.us


Quick Facts:
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Total number of onsite systems: 1.6-2 million, estimated.
Number of new systems installed each year: About 40,000.
Failure definition: Conditions which prohibit the system from functioning in a sanitary manner,
and which result in plumbing failure, or in the discharge of insufficiently treated water onto the
ground, or into surface or ground waters.
Number or proportion of systems presently failing: NA, see below for annual estimates.
Number or proportion repaired annually: 20,000-30,000 indefinitely repaired or replaced
annually; data are tracked well because all repairs require permits.
Number or proportion replaced annually: See above.
Number or proportion of repairs or replacements that require alternative technology (e.g.,
sand filters, pressure dosing):
Many types of alternative or advanced technology are employed,
but no percentages were provided. As to leaching areas, over half the systems are either
conventional trench or bed systems. However, fill systems account for 20%, mound systems for
almost 25%, and gravelless systems for about 1.5% of current installations.
Number or proportion of repairs or replacements that require advanced technology (e.g.,
disinfection, nutrient removal):
No breakout was provided; see above.
Cost of a conventional septic system installation: $2500; range $2000-$25,000. About half the
installations require mounds or fill; were this not the case, the typical cost would be more like
Cost of a centralized sewer tie-in (including fees and cost of the sewer lateral): $3000 to


Septic Stats:
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DELAWARE 666,168 289,919 220,935 62,267 6,185 532 212,793 74,541 2,585
KENT 110,993 42,106 22,418 17,776 1,757 155 23,606 18,060 440
NEW CASTLE 441,946 173,560 162,554 9,110 1,688 208 160,902 12,142 516
SUSSEX 113,229 74,253 35,963 35,381 2,740 169 28,285 44,339 1,629


Onsite Demonstration Programs:
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No information is available on Onsite Demonstration Programs in Delaware.

Onsite Management Communities:
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No information is available on Onsite Management Communities in Delaware.