Septic Systems

The United Stated Environmental Protection Agency defines a septic system aa an underground wastewater treatment structure, commonly used in rural areas without centralized sewer systems. Septic Systems use a combination of nature and proven technology to treat wastewater from household plumbing produced by bathrooms, kitchen drains, and laundry.

A typical septic system consists of a septic tank and a drainfield, or soil absorption field.

The septic tank digests organic matter and separates floatable matter (e.g., oils and grease) and solids from the wastewater. Soil-based systems discharge the liquid (known as effluent) from the septic tank into a series of perforated pipes buried in a leach field, chambers, or other special units designed to slowly release the effluent into the soil.

Alternative systems use pumps or gravity to help septic tank effluent trickle through sand, organic matter (e.g., peat and sawdust), constructed wetlands, or other media to remove or neutralize pollutants like disease-causing pathogens, nitrogen, phosphorus, and other contaminants. Some alternative systems are designed to evaporate wastewater or disinfect it before it is discharged to the soil.

Septic System Process


Planning Documents

Helpful Resources

Betterment Loan


Septic fees


Well Water Testing

  • Bottles may be purchased at your local pharmacy
  • Samples must be received by 9:15 am on Tuesdays
  • Do not open the bottle until you are ready to fill
  • Do not touch the inside of the bottle or cap
  • If filling the bottle from the outside remove hose and sterilize spigot
  • If filling from inside, remove any filters or screens
  • Allow the cold water to run for 3 to 5 minutes before filling the bottle
  • Do NOT let the mouth of the bottle touch the tap
  • Fill bottles the morning of drop off
  • Please fill out the appropriate form
  • A check for $45.00 for Barnstable County Lab
  • A check for $5.00 for the Town of Nantucket

Please bring water samples to the Health Department office located at 3 East Chestnut Street. Nantucket, MA 02554
If a specific test is required, please contact the Barnstable County Laboratory for instructions. 508-375-6613 or

More information on wells: