A new demonstration project in Tisbury and Oak Bluffs aims to collect valuable data on urine diversion, a simple and relatively inexpensive way to improve water quality in coastal ponds. The technology also has the potential to support local agriculture and year-round housing development in the region.

Urine diversion (UD) uses specially designed toilets to separate urine and solids at the source. The urine can then be stored for use as fertilizer, while solids go into the sewer, septic tank, or other system. Diverting urine reduces the main source of nitrogen pollution in coastal ponds.

“When you think about scalability on this, versus scalability and timing on sewer or [denitrifying] systems, it makes a lot of sense,” said Sherry Countryman, President of the Lagoon Pond Association, which spearheaded the project along with MVC Water Resources Planner Sheri Caseau last year. “One of the reasons we got really excited about urine diversion was we could start doing it right away.”

The plan is to install up to 50 residential systems in the Lagoon Pond watershed next spring and monitor them for three years. Partners include the Massachusetts Alternative Septic System Test Center (MASSTC) in Sandwich, MA Depts. of Environmental Protection (DEP) and Agricultural Resources (MDAR), Vermont-based nonprofits Rich Earth Institute and Nutrient Networks, The Green Center (a Falmouth-based ecological design nonprofit), Brightwater Tools (a company focused on sustainable sanitation technology), and various Island boards, farmers, and wastewater professionals.

The Tisbury and Oak Bluffs boards of health, along with the Tisbury selectboard and Sewer Advisory Committee, formally approved the proposal this year. Several other groups, including Tisbury Waterways Inc. and Friends of Sengekontacket, have also shown support. The MVC publicly endorsed the proposal in March.

Read more in the June 2026 newsletter.