All dishwasher detergent sold in Massachusetts must be nearly phosphate-free, eliminating a significant source of phosphorus in wastewater. Phosphorus acts like Miracle-Gro when it enters our rivers and lakes, causing dense algae and aquatic weed growth which smothers aquatic life and is unsightly and smelly. Of the phosphorus found in municipal wastewater, dishwashing detergent accounts for 9 to 34 percent. Wastewater treatment plants and septic systems remove some phosphorus, but if less goes in, then less has to be removed, saving municipalities money and protecting our water resources.

Phosphate-free laundry detergent was required in the 1970s in response to severe water pollution problems, but not until February 2008 did the Massachusetts legislature require retailers to sell only dishwasher detergent containing less than 0.5% phosphate. Some dishwasher detergents contain up to 9% phosphate. OAR has advocated for a phosphate ban for over a decade, and many of the watershed's elected representatives have actively supported the legislation, spearheaded by former State Senator Pam Resor. In 2010, dishwasher detergent phosphate bans also took effect in 15 other states. .

Other phosphorus sources to think about:
Significant quantities of nutrients are also carried into our three rivers and tributary streams from lawns, streets, and parking lots by storm water runoff.

Another source of phosphorus in your household is food waste, that is the scraps of food you wash down your sink and especially the food ground up in a food disposal or "pig," if you have one. Instead of sending this phosphorus-rich material to your community's wastewater treatment plant, compost it!