From KUNC (Luke Runyon):
Since the 1990s, a strange phenomenon has played out in arid Western urban areas. Populations are booming while overall water use is staying the same or going down. The trend is clear in Denver, Albuquerque, Las Vegas, San Diego and Phoenix: Cities are growing and using less water in the process.
It’s impossible to give credit to one single solution, but one could make a strong case that the M.V.P. award for water conservation efforts should go to the modern toilet.
The toilet is the single largest user of water in the home. It uses more than the washing machine, the dishwasher, the shower or the kitchen faucet. About a quarter of all water that enters a home will flow through the toilet according to a 2016 study. Each day the average toilet will use about 33 gallons of water.
That might sound like a lot, but it’s a big improvement. In 1999 the average toilet guzzled more than 45 gallons of water daily…
The road to high-efficiency toilets began back in 1992. The concern was less about water scarcity in the West and more about overwhelmed sewage systems on the east coast.
Congress was feeling pressure to pass national standards for water use and came up with the Energy Policy Act, a law that spawned a generation of low-flow fixtures.
For the plumbing industry, it was a huge deal.
“Absolutely, it was an extremely watershed moment, no pun intended,” says Pete DeMarco with the International Association of Plumbing and Mechanical Officials.
The law mandated that toilets only flush using 1.6 gallons of water or less. Throughout the 1990s, low-flush toilets flooded the market. DeMarco says even though the regulations received input from toilet manufacturers, the new models received heaps of scorn from users who complained that their new and improved toilets performed worse, unable to finish the job in a single flush.
“There were some poor-performing products back in the mid-90s. I think the regulation caught some manufacturers off guard,” he says.
In many cases, DeMarco says, manufacturers had simply reduced the amount of water a toilet used without making significant changes to its inner workings. A lower flow just couldn’t cut it.
The frustrated customers sent toilet-makers back to the drawing board. A new test from a company called Maximum Performance allowed manufacturers to demonstrate that their low-flow toilets could actually evacuate the bowl with one flush. In simulations, toilets would be loaded up with logs of miso paste to show their effectiveness.
DeMarco says toilets can’t take all the credit, but this one innovation is a big reason why cities have been able to grow and still keep their water use in check. Indoor use dropped 22 percent nationwide between 1999 and 2016, much of that due to swapping out old fixtures.
In recent years some states with water scarcity problems — like Colorado and California — have passed even tighter regulations on how much water toilets can use…
Even though some conservationists feel like the indoor water use fruit has been plucked, a 2017 Alliance for Water Efficiency study found that more than 13 million non-efficient toilets — those that flush more than 1.6 gallons — remain installed in five states: Arizona, California, Colorado, Georgia and Texas.
A nationwide push to rid the country of old toilets could have a significant effect.
If all toilets were high-efficiency indoor water use could drop an additional 35 percent to below 40 gallons per person per day, the study projected…
This story is part of a collaborative series from the Colorado River Reporting Project at KUNC, supported by a Walton Family Foundation grant, the Mountain West News Bureau, and Elemental: Covering Sustainability, a new multimedia collaboration between public radio and TV stations in the West, supported by a grant from the Corporation for Public Broadcasting.