Laws that took effect in 16 states on July 1 limit phosphorus in household dishwasher detergents to 0.5 percent. (Previous products could contain up to 8.7 percent.) As a result, major manufacturers have reformulated their products for the whole U.S.
Early efforts at limiting phosphates, the phosphorus-containing compound in detergents, left some residents of affected states smuggling higher-phosphate detergents into their homes. Indeed, the handful of low-phosphate products we tested for our last dishwasher-detergent report tended to perform worst overall.
This time, all the detergents are low- or no-phosphate, and there's better news: Although none equaled the excellent (but now discontinued) product that topped our Ratings in August 2009, seven were very good. Here's what else we found:
Top-rated Finish Quantum has chlorine bleach, but the next four have no bleach. It didn't seem to act on our baked-on soils, but bleach might help with tea or similar stains.
Most of the tested detergents have enzymes, which can break up food for easier removal. Of the five with no enzymes, four were only fair overall; the fifth, Cascade Complete All in One with Bleach Hydroclean, was good.
This time, tablets and pacs tended to score high and gels low, but it's too soon to say whether that trend will continue.
Don't just buy by brand. Cascade and Finish products were scattered throughout the Ratings.
A canister that dispenses 12 doses from a cartridge automatically, Finish Quantumatic lets you avoid pouring detergent repeatedly. It performed well but takes up space in the dishwasher and costs about $10 for the dispenser and first cartridge.
Note that we tested phosphate-free Martha Stewart Clean liquid dishwasher detergent, but the company said its formula changed again after our tests. The old version would have been lowest-rated of all—as was Martha Stewart Clean Laundry Detergent in recent tests.
There are several very good products from which to choose. Finish Powerball tablets are least expensive, at just 22 cents per load, and bested some detergents that cost more.