Do automatic-flush toilets save water?

04/14/2014 12:00 AM

10/08/2014 11:52 AM

Most times when I use an automatic-flush toilet in a commercial building, it flushes two to three times. Do automatic-flush toilets waste or save water? – Ed Zajac, Orangevale

Your experience is common, and it seems these devices do not save water. According to several studies, they may actually use significantly more than old-school manual valves.

John Koeller, a Yorba Linda-based engineer and water-efficiency expert, said the primary benefit of automatic- or sensor-flush plumbing fixtures is improved hygiene, not water savings. Koeller is a partner in an organization called MaP Testing, which for years has conducted independent testing of various plumbing fixtures.

In 2010, Koeller and a colleague studied sensor-flush toilets in the real setting of a Florida office building. After months of monitoring, they found that sensor-flush toilets actually increased water consumption by 45 percent compared to manual-flush toilets. The cause was so-called “phantom flushing,” or multiple false flushes produced by over-active motion sensors on the toilets.

“It’s a big problem. It’s a problem also with urinals,” Koeller said. “A lot of manufacturers do not like these studies to be out there. Water-efficiency people like myself, they don’t recommend sensor-flush valves.”

The problem is that most toilet motion sensors point out into the room or the stall, where there can be lots of motion. He said one manufacturer, Kohler, makes a motion sensor that avoids this problem. The sensor points straight up, and the user must wave his or her hand above the sensor to flush the toilet.

– Matt Weiser

Summer recreation is a big deal in my family – boating, specifically. How far will we need to go this summer to find a suitable body of water? – Thomas Sherer, Roseville

Look no further than Folsom Lake.

Lake levels have risen dramatically during the last two months, thanks to several wet storms. As of April 3, the lake contained 454,000 acre-feet of water, roughly triple the amount it contained in late January.

While some reservoirs in the state remain depleted, Folsom Lake levels are now at more than 70 percent of normal for the date. The Sierra Nevada snowpack remains well below average, but as it melts, the lake will continue to rise, making for good boating. Just don’t put off the fun: Lake levels could be low again by Labor Day, based on historical trends.

– Phillip Reese

As a gardener of fruits and vegetables, I want to know how I can get the most bang for my bucket of water. Which of the commonly grown spring/summer plants – such as tomatoes, zucchini, beans – yields the most produce per volume of water? If you had limited water to use on a garden of edibles, what would you select to grow this summer of drought? – Melanie Loo, Sacramento

Grow beans. They have built-in drought resistance.

Beans native to the Southwest or other areas with hot summers and little rain can do well this summer in Sacramento.

Black-eyed peas need hot temperatures to produce good crops and like less water, not more. Lima beans can get by on limited water, too. Snap beans and pole beans have short growing seasons and will set crops with little water.

Tomatoes, melons and squash grow deep roots that seek out water. Those deep roots benefit from weekly deep irrigation. Dark Star, a variety of zucchini, is especially adept at producing a large crop with limited water.

Several melon varieties recommended for hot, dry summers by Southern Exposure Seed Exchange: Missouri Gold; Top Mark; Sweet Passion; Kansas; Edisto 47; and Crimson Sweet and Strawberry watermelon.

Sacramento radio host Farmer Fred Hoffman recently compiled a list of drought-tolerant crops for Sacramento home gardeners. He included okra (Gold Coast, Stewart Zeebest, Beck’s Big Buck); eggplant (Listada de Gandia, black beauty, Ping Tung Long); peppers (Carolina wonder, Charleston belle, aji dulce); cucumbers (little leaf H-19, Ashley, Suyo long); squash (Moschata, Tromboncino, Waltham butternut); and pumpkin (Seminole).

If trying to decide between two varieties, look at their leaves. Vegetable plants with smaller leaves tend to lose less moisture due to transpiration. Veggies with big, floppy leaves will suffer more in drought conditions.

As for what not to plant: Skip the corn; it’s a major water hog and does not form ears well when irrigation is cut back.

Shallow-rooted lettuce is not drought tolerant (and usually struggles during Sacramento summers anyway), so cut back on summer greens – or grow them in pots on a patio with dappled sun where they can get some shade (and attention if they wilt).

– Debbie Arrington

Editor's Choice Videos

 

Join the Discussion

The Sacramento Bee is pleased to provide this opportunity to share information, experiences and observations about what's in the news. Some of the comments may be reprinted elsewhere on the site or in the newspaper. We encourage lively, open debate on the issues of the day, and ask that you refrain from profanity, hate speech, personal comments and remarks that are off point. Thank you for taking the time to offer your thoughts.

Terms of Service