On-Site Wastewater Disposal Systems

How to Obtain a Site Evaluation, Septic Permit and a Licensed Contractor

A Quick Guide Through the Three-Step Process

Obtaining an on-site wastewater disposal system (OWDS) in Delaware is a three-step process. Chapter 60, Title 7 of the Delaware Code ensures that a site evaluation must be performed on unimproved lots prior to sale.

Step 1: Have a site evaluation performed by a licensed Class "D" site evaluator to determine what type of disposal system, under current regulations, can be sited on the parcel.

  • Site evaluator performs field work, prepares site evaluation report and submits it to the Department of Natural Resources and Environmental Control (DNREC), with appropriate fee, for approval.
  • DNREC reviews work and approves the site evaluation within 10 calendar days of receipt.
  • Approved site evaluation is mailed to owner or authorized agent (can be picked up on request).

Step 2: Hire a licensed system designer to design the OWDS and obtain a permit.

  • Select a Class "B" designer for gravity systems and standardized pressure-dosed systems.
  • Select a Class "C" designer for engineered systems.
  • All designs are submitted to DNREC with appropriate fee, once approved they become permits.
  • Gravity permits - approximately 10 working days from time of receipt to final approval.
  • Engineered permits - approximately 20 working days from time of receipt to final approval.

Step 3: Choose a licensed Class "E" contractor to install your OWDS.

    Note: Listings of all licensees and copies of the Regulations Governing the Design, Installation and Operation of On-Site Wastewater Treatment and Disposal Systems can be obtained from DNREC offices located in Dover and Georgetown. Contact the Customer Services Section toll-free at 1-800-273-9500 if you have questions or need directions.

Do's & Don't's For The Lifespan of Your On-Site Wastewater Disposal System

Do

  • Reduce the amount of water used by taking shorter showers, installing a water-saver shower head or both. Low-flow shower heads can reduce water consumption from five or six gallons per minute to as little as two gallons per minute.
  • Use faucet aerators in the kitchen and bathroom sinks. They will reduce water usage by about 50 percent.
  • Use your dishwasher and washing machine sparingly. Do full loads and average one load per day to let your drainfield accept the amount of wastewater you are generating.
  • Install low-flush toilets in your bathrooms or, if you have an older toilet, use a device which will displace some of the water needed to fill the tank. A plastic jug filled with water works well or, if your finances allow, replace the older fixture with one that has a smaller tank. The low-flush tanks use only a few quarts of water per flush. Reduced number of flushes can also be a water-saving technique.
  • Use biodegradable toilet paper. Many products are labeled "approved for septic tank use."
  • Have your septic tank pumped regularly. This is usually every three years but it depends upon your family size, amount of wastewater generated and the age of the system. If you have a garbage disposal you may need to pump more frequently. Ensure the wastehauler pumps both compartments of your tank through the manhole cover, not the inspection ports, and that all the sludge is removed. Keep the manhole location marked for easy accessibility.
  • Contact a licensed installer whenever you have a problem with your disposal system or suspect it may be failing. Contact DNREC to determine the proper action to resolve the problem.

Don't

  • Construct buildings or allow vehicular traffic over your drainfield and replacement area. Either may result in costly damage.
  • Plant any deep-rooted trees or shrubs within 10 feet of your disposal system. The roots can grow into the drainfield and reduce its capacity to handle wastewater.
  • Pour grease, paints, caustic or oily liquids, fuels, cooking fats or motor oils into sinks or toilets. These can kill the bacteria and/or plug your disposal system.
  • Repair your disposal system without obtaining the proper permit from the Ground Water Discharges Section of DNREC. Only use Class "E" licensed contractors when doing repair work.
  • Climb into a septic tank. Methane and hydrogen sulfide gases, which are present from the decomposition processes, may cause illness or death.
  • Dispose of coffee grounds, sanitary napkins, tampons, condoms, cigarette butts, or disposable diapers in the toilet or sink.

How Your On-Site Wastewater Disposal System Functions

On-site wastewater disposal systems are water treatment facilities located within your property boundaries that collect, treat and dispose of wastewater. They differ from municipal wastewater treatment facilities which receive wastewaters from other locations for treatment. The on-site wastewater disposal system can consist of several components: septic tank, distribution box, dosing chamber and drainfield. If properly maintained, a disposal system can last 15 to 20 years.

The purpose of the septic tank is to collect and partially treat household wastewater. In the tank, solids separate from the liquids and bacteria begins to breakdown the wastes. Approximately 60 percent of the solids are broken down by the bacteria into liquid and gas. During the two-to-three day treatment period the lighter-than-water solids such as greases, oils and toilet paper float to the top and form a scum layer. The solids, which are heavier than water, sink to the bottom forming sludge. The cloudy water in between is known as effluent.

The processes in a septic tank take place anaerobically, which means without the presence of oxygen. The gas produced is discharged through the plumbing vent system on the roof of the house. Methane and hydrogen sulfide are gases produced through these natural processes. They are extremely dangerous. You should exercise extreme care when inspecting or looking into your tank.

The final treatment step for the effluent, as it returns to the groundwater, involves the drainfield. The drainfield may be referred to as a soil absorption system, leach field or a disposal field. It is a series of perforated pipes placed in either a gravel-filled trench or bed or placed in gravel-less chambers to evenly distribute the effluent. The wastewater slowly trickles through these materials and into the soil beneath. Soil bacteria breakdown the effluent aerobically, which means with the presence of oxygen.

As the effluent seeps into the soil and approaches the natural groundwater it is purified by other soil components in conjunction with the bacteria. Toxins, viruses and other pollutants are removed from the wastewater. Clay particles located in the soil chemically attract and hold sewage nutrients (phosphates and nitrates), heavy metals and disease-carrying organisms. However, chemical additives, paint, grease, fats or thinners will kill the bacteria and clog the drainfield, contaminating the groundwater. Over time, these products can render your drainfield ineffective.

How to Repair or Replace a Malfunctioning On-site Wastewater Disposal System

A malfunctioning or failed on-site wastewater disposal system is not only a nuisance but a public health hazard. Repairing or replacing a problem system will protect your family, friends and drinking water. But, how do you know your on-site wastewater disposal system is malfunctioning? Here are some warning signs to look for in your house and yard:

House:

  • Slow draining sinks and toilets
  • Plumbing backups
  • Gurgling in the plumbing

Yard:

  • Damp soil or ponding over the system
  • Grass grows faster and greener
  • Sewage odor near the system

If you discover one or more of these warning signs contact a licensed contractor to have your system inspected. You may want to contact DNREC to inform them of your troubles. Together, DNREC and the contractor will advise you about what they find and what course of action to take.

Sometimes, depending on the type of system, minor adjustments can be made to correct your problem. Repairs can be made to help cure some problems, such as excessive water usage, improper sizing of the drainfield or replacing older septic tanks. As an example, additional drain lines may be added to the drainfield if a site evaluation indicates that conditions allow. Or, a component replacement permit may be used to replace a metal or older concrete tank.

If the disposal system has failed, you must replace it. The replacement system must conform to the current criteria cited in the regulations.

State Funds Available to Repair/Replace Failed Wastewater Disposal Systems

DNREC has dedicated a portion of the State Revolving Fund (SRF) to help Delawareans pay for the cost of repairing on-site wastewater disposal systems that are malfunctioning. Low interest loans are available to low-to-moderate income homeowners. As these loans are repaid, the money is returned to the revolving fund to make more low interest loans to other Delawareans.

Established by HUD- Effective December 27, 1997
Household Memebers Sussex County Kent County New Castle County
1
$ 31,740
$ 32,890
$ 46,345
2
$ 36,225
$ 37,605
$ 53,015
3
$ 40,825
$ 42,320
$ 59,570
4
$ 45,310
$ 47,035
$ 66,240
5
$ 48,990
$ 50,830
$ 71,530
6
$ 52,555
$ 54,510
$ 76,820
7
$ 56,235
$ 58,305
$ 82,110
8
$ 59,800
$ 62,100
$ 87,400

  • The interest rate is 3 or 5 percent, dependent upon income.
  • The minimum monthly payments are 1.5 percent of the family income or $10 per month, whichever is greater.
  • The loan terms, up to 20 years, vary in accordance with the amount borrowed and the rate of the repayment.
  • The loan can be used to cover the costs of the site evaluation, system design, permit(s), installation of the system and any related loan closing fees.

Please contact the Facility Support Branch of DNREC for information about the SRF loan program. The toll-free number is 1-800-273-9500. There is a $30 non-refundable application fee. An interview with the Facility Support Branch may be necessary when processing your application. All information you supply with your application will be kept strictly confidential.

Record-Keeping Tips for Repairs and Maintenance Purposes

Knowing the location of your on-site wastewater disposal system is very important for repairs, pumping and traffic avoidance. All information pertaining to the disposal system should be filed together for safe keeping. Record-keeping will help answer questions and serve as a reference when determining maintenance intervals. This brochure could be used to hold this important information. The following list is a good guide for important record-keeping items.

  • File detailed records of all maintenance performed, inspections and any problems.
  • Obtain a copy of the permit from the contractor or DNREC and keep in the file.
  • Make a map or drawing of the location of your on-site wastewater disposal system if unable to get a copy of the permit.
  • Keep receipts and a record of pumping dates; a septic tank pumping log is included with this guide.

Fact Sheets on the different Disposal Systems

This brochure was designed and compiled by Jack Hayes, Environmental Scientist, DNREC, with assistance from Burns & Ellis Realtors, Clean Delaware, Inc., Eastburn JOAT, Eastern Shore Soil Services, Hollis Warren Waste Water Mgmt., Inc., Ken Darling & Sons, Inc., WWES, Inc. and numerous DNREC employees. Funding was provided by a NonPoint Source 319 Grant and a contribution from Clean Delaware, Inc. Doc. # 40-08/96/09/04
c1996 Department of Natural Resources and Environmental Control (DNREC)

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