A cesspool is a wastewater disposal method that does not involve any wastewater treatment. Essentially, household wastewater flows directly into a hole in the ground. The hole typically has an open bottom and some have perforated tile or concrete on the sides. There is a lid where the cesspool can be accessed for pumping, but it is sometimes buried underneath grass or vegetation.

Cesspools are banned because they do not provide adequate wastewater treatment and contribute to sewage pollution in our water resources. Additionally, some cesspools are structurally unsound and therefore dangerous, as they can collapse.

A septic system is an onsite wastewater treatment system where wastewater first flows into a septic tank, where fats and oils rise to the top and solids sink to the bottom. The remaining liquid waste is dispersed into the ground in a leach field. Septic systems are an improvement on cesspools, which discharge directly into the ground with no treatment, but these systems are outdated and still cause nutrient pollution to water resources.

Nature-based individual wastewater systems, aerobic treatment units, or neighborhood-scale cluster systems can all provide wastewater treatment with minimal environmental impact. WAI is working on bringing innovative, sustainable wastewater technology to Hawaii - check out our Partners page for more information on these innovative options.

All cesspools in Hawaiʻi must be converted by 2050 (Act 125). However, it is likely that high-priority areas will have to convert earlier. Proposals for earlier deadlines for cesspools that are at high risk of causing pollution will be heard in this year’s legislative session.

The typical cost to convert a cesspool to an individual wastewater system is $30,000-$50,000. WAI recognizes that this cost is difficult or impossible for many homeowners to afford, so we are working to bring grant and rebate programs to homeowners to help with the costs.

Currently, the USDA Rural Development program provides low-interest loans for wastewater upgrades in rural areas. WAI is working with the state and county governments to administer grant programs such as the recently passed HB2195, which will provide up to $20,000 in grants or rebates to low-moderate-income homeowners for cesspool conversions. Sign up for our newsletter and follow us on social media to stay up to date on new financial aid opportunities @waicleanwater on Facebook, Instagram, and LinkedIn.

In Hawaiʻi, the Department of Health oversees individual wastewater systems, and the county governments oversee municipal systems such as sewer. Permits for individual wastewater systems will be handled by your engineer and approved by the Department of Health.

Yes. Hawaiʻi was the last state to ban cesspools by over 30 years!

States on the east coast have required cesspool conversion when properties are bought and sold. Suffolk County in Long Island, New York, has helped homeowners with the costs of cesspool conversion by compiling funds from local and federal programs along with a sales tax to go towards water protection.

The first step is to contact a licensed engineer who can help you assess options for your property. Check out our Potty Portal for a list of qualified engineers and installers in your area.

If the sewer is in your neighborhood and you are not connected, contact your county wastewater office to inquire about connecting to the sewer. Make sure you have your TMK (tax map key) number handy.

Honolulu County: (808) 768-8210; Department of Environmental Services

Kauai County: (808) 241-4082; application to connect to public sewer

Maui County: (808) 270-7417; sewer website

Hawaii County: (808) 961-8615; Wastewater Division Website

Sewer expansion will be determined by the counties. Some areas are already slated for sewer expansion. Follow us on social media and subscribe to our newsletter to get important updates as new areas are added to the sewer expansion list.

The Department of Health provides the following guidance:

Upgrades from cesspools are required by DOH under the following circumstances:

Your cesspool has been pumped more than twice or has spilled more than once in 12 months.

You are applying for a building modification for adding an enclosed area such as a bedroom or an ADU.

You are changing the use of your property: i.e, from residential to commercial.

You are applying for a building modification (example: adding carport, lanai, bathroom) and your cesspool discharges into the groundwater.

Currently, you do not need to convert your cesspool to sell your house, but this may soon change. Legislation to require conversion at the home sale is being heard in the upcoming legislative session. If you are interested in policy, email info@waicleanwater.org to join our volunteer Legislative Task Force!

Cesspools release excess nutrients and harmful pathogens and toxins into the marine environment via groundwater contamination or overflows. These pollutants harm the nearshore environment by encouraging the spread of invasive algae, increasing rates of coral disease, and degrading habitat complexity.

Yes, even if your cesspool is not near the coast, it can cause water pollution. If you are above a drinking water aquifer, cesspool pollution can get into the drinking water. In some areas of Hawaiʻi, such as Hawaiian Paradise Park in the Keaʻau area of Big Island, fecal indicator bacteria has been observed in up to 50% of wells. Also, contaminated groundwater runs downslope and will eventually reach the ocean, even if the travel time is longer than from a cesspool right on the coast.

Various organizations test the water quality at beaches throughout Hawaiʻi. Links to their water quality data can be found on our Water Quality page. Check back soon for an interactive map to see what is known about sewage pollution in your watershed!

Yes, pathogens in sewage can leach from cesspools into streams and the nearshore ocean, and these can make you sick. Skin infections and gastroenteritis are two common health impacts of swimming in polluted water. If you get sick after swimming, please fill out our Sea Sick survey so we can identify “hot spots” for public health risk.