Delaware Private Well Testing

There is no single universal panel required for every Delaware home. Here's how to choose parameters and get tested properly.

Private wells

Short answer: Start with current DPH kit or laboratory guidance for a basic panel, then consider additional property-specific parameters based on your location, well construction, nearby land use, symptoms, and professional advice. Sampling instructions must come from the lab, not a general online guide.

Basic vs. expanded testing

A basic potability panel typically covers bacteria and a few common chemical parameters. Depending on your property, you may also want to test for parameters more specific to your region or situation. Do not treat a basic panel as a complete risk assessment for every possible concern.

Delaware test kits and location-specific add-ons

Delaware DPH describes a bacteria kit for total coliforms and E. coli, plus a chemical kit for alkalinity, chloride, fluoride, hardness, iron, nitrate, nitrite, pH, sodium, and sulfate. The state has offered these kits free to Delaware primary-residence well owners; confirm current availability and pickup instructions before sampling. For coastal Sussex, add chloride/salinity context; for agricultural parts of Sussex and Kent, discuss nitrate and nitrite; and for a suspected plume or industrial history, use a certified laboratory for parameters outside the DPH kit.

Potential parameters to consider

Total coliform / E. coli
Nitrate / nitrite
pH
Iron
Manganese
Hardness
Chloride / salinity (especially in coastal Sussex County)
Sulfate
Arsenic where appropriate
VOCs where appropriate
PFAS where appropriate
Pesticides where appropriate

Step-by-step

Contact Delaware DPH-connected resources or a certified laboratory to obtain a test kit or arrange sampling.
Follow the lab's sample collection instructions exactly — do not improvise your own method.
Choose additional parameters based on your location (see county-specific concerns), well construction, and any symptoms like taste, odor, or staining.
Submit the sample within the lab's required timeframe.
Review results against comparison values with the lab or a qualified professional.
Retest after any treatment, repair, or disinfection.

Sampling details that change the result

Use the bottle supplied for the requested analysis and follow the collection, preservation, and delivery window exactly. A sample from a treatment faucet, a hose, or a recently disinfected line may not represent raw well water. Tell the laboratory whether the sample is before or after treatment and whether the property has been vacant. For bacteria, avoid touching the inside of the cap or bottle; for chemistry, do not rinse a preserved bottle unless the laboratory instructs you to do so.

When the standard kit is not enough

The DPH kit is a useful Delaware starting point, not a complete environmental investigation. Ask about VOCs, pesticides, PFAS, arsenic, or other analytes when there is a documented nearby source, a DNREC investigation, a fuel or solvent history, unusual results, or a professional recommendation. Private laboratories may use different panels and prices, so compare the analyte list, reporting limits, certification, sample requirements, and turnaround time rather than choosing the cheapest label.

Common mistakes

Assuming one panel is legally required for every home
Skipping the lab's specific collection instructions
Treating a basic bacteria/nitrate test as a complete PFAS or VOC screen
Not retesting after repairs or treatment

Build a useful testing record

Write down the well permit number, well depth if known, pump and treatment equipment, date of collection, whether the property was occupied, and whether the sample was collected before or after treatment. Keep the laboratory report and chain-of-custody information together. That history helps explain why two samples differ and gives a well professional or health official enough context to recommend the next panel.

For a new owner, a practical baseline is the Delaware DPH bacteria and chemistry kit, followed by location-specific testing. For a coastal property, chloride and sodium deserve attention; for agricultural Sussex or Kent, nitrate and nitrite deserve attention; for a documented release or unusual odor, ask a certified laboratory about VOCs, pesticides, PFAS, or other targeted analytes.

When to contact a laboratory or professional

Contact a certified laboratory for testing kits and analysis. Contact a well professional for construction-related questions. Contact your health-care provider for medical questions related to a result.

Official sources

Delaware DPH private-well kit analytes and assistance
Delaware Public Health Laboratory private-well testing
DNREC Well Permits and licensed well-contractor requirements
DNREC Water Well Licenses

Is there a free or reduced-cost testing option in Delaware?

Contact Delaware DPH-connected resources for current information on test-kit assistance and pickup locations, since availability and cost can change.

This page provides general educational information and is not medical or laboratory advice.

Last reviewed: 2026-07-11. Report a correction.