My new dishwasher has receptacles for both soap and “rinse-aid.”

My new dishwasher has receptacles for both soap and “rinse-aid.” Is rinse-aid safe for the environment, and do I need to use it in my dishwasher?

—Britten Clark, Seattle, WA

If your region”s water source is rich in magnesium and calcium salts (“hard” water), adding rinse-aid to your dishwasher along with the detergent may help prevent streaks and spotting on your glassware and dishes.

Rinse-aid—the ingredients of which are usually ethanol, citric acid, sodium, dyes and acrylic acid polymers—breaks down the salts in hard water, thereby preventing the adhesion of soap clumps during the rinse cycle, leaving cleaner-looking results (although consuming food and drinks from streaked or spotted dishes and glassware is not a health hazard in its own right). The National Institutes of Health report that most rinse-aid is completely biodegradable, and while it is neither carcinogenic nor dangerous if used properly, it can cause eye and skin irritation following prolonged exposure and should not be ingested, of course.

While the use of rinse-aid to combat dishwasher streaking is no environmental crime, those concerned about the consumption of resources might think twice about the need for it. Mainstream rinse-aid, like dishwasher soap itself, contains phosphates in its cleaning agents. Wastewater containing phosphates which escapes sewage treatment can cause excessive algae growth in waterways which in turn pollutes drinking water and leads to marine “dead zones”—underwater environments deprived of oxygen and thus unable to support life. Consumers should keep in mind that dishwasher soaps, as well as laundry detergent and many other household items, also contain phosphates that can cause problems if not disposed of properly.

It”s easy to avoid rinse-aid and other household items with phosphates by seeking out products from any of several companies that only use plant-based ingredients. Earth Friendly Products, Ecover and Simply Clean, to name just a few, make environmentally friendly rinse-aid that can be found in most natural foods markets. Beyond avoiding phosphates, these companies also pride themselves in avoiding petrochemicals and dyes in their products.

Also, just because your dishwasher may need rinse-aid does not mean you should fear drinking hard water from the tap. According to the U.S. Environmental Protection Agency (EPA), drinking hard water regularly poses no health threat and can actually help lower the incidence of heart disease, as the abundant magnesium and calcium salts help break down arterial plaque in the bloodstream.

CONTACTS: Earth Friendly Products, (800) 335-3267, www.ecos.com; Ecover, www.ecover.com; Simply Clean, www.simplyclean.ca; U.S. Environmental Protection Agency, www.epa.gov.