With millions of people worried about California’s historic drought, a proliferation of free apps turn water conservation into a game while letting consumers save both water and money around the house.

Many are aimed at both children and adults and award points through quizzes and by adopting water-saving tips. Some turn water conservation into a competitive game with other family members to see who can save the most water — and money — by, say, taking the quickest shower.

And at least one makes it easy to take photos of neighbors who drown their lawns in water — and then report them to local water authorities.

The Santa Clara Valley Water District does not have a water conservation app of its own. But it does have an online water use calculator on its website that was developed during the 2010 drought to help customers understand the cost of using too much water.

So, during the current drought, the water district supports any apps that let water users track their personal water consumption through their handheld devices.

“Anything that people can do to identify ways to use water more efficiently, we’re all for it,” said Marty Grimes, spokesman for the Santa Clara Valley Water District.

Lori Palmquist, of Richmond-based WaterWonk, is getting ready to launch three apps aimed at helping commercial landscapers save money by better managing their water.

But Palmquist is also in favor of apps aimed at helping average consumers save money by cutting down on their own water use at home.

“Whether it’s apps that allow them to find leaks or cut down on their water use indoors or outdoors, it’s essential — really, really essential — for everyone to have this information,” Palmquist said.

Many free apps, like the National Ground Water Association’s water usage calculator, take a straight-forward approach to estimating water use through dishwashers, toilets and showers.

Others, such as the Drip Detective app, up the ante by having users tap their screens every time a drop falls out of a leaking faucet. Or they can measure the rate of a more serious leak, whether by teaspoon, tablespoon, pint or gallon.

Either way, Drip Detective then calculates the amount of water — and money — being wasted every day, week, month and year based on your current water bill.

Like other water-conservation gaming apps, H20 Tracker awards points by correctly answering quiz questions such as whether more water is spent taking a bath or washing a car.

Unlike most water-conservation game apps, however, H20 Tracker, makes it easy for users to inform on their water-wasting neighbors.

“Is someone letting water run down the street?” reads the description for H20 Tracker. “Let your city know! You can even take a picture and send it with your report.”

Other game apps are clearly aimed at educating a new generation about the importance of water conservation, such as “Captain Plop’s Water-Saving Mission” by the South Australian Water Corp., one of several Australian organizations that have developed water conservation apps.

It’s basically a children’s e-book about the adventures of a colorful blue cartoon character named Captain Plop whose head is shaped like a water drop.

Readers follow Captain Plop as he navigates the inside of a home’s pipes. Along the way, Captain Plop offers lessons on the importance of saving water by turning off the tap while brushing teeth or taking shorter showers.

Another game app, “Tap The Tap,” also uses a cartoon icon in the form of a water-conscious camel to teach the importance of water conservation.

Throughout the game, which involves tapping on the correct plumbing pipe, players are encouraged to pledge to use water wisely.

Whether it’s a staid app about money that’s wasted through a leaking faucet, or a colorful interactive children’s game, Palmquist likes the idea that consumers can access so many free, water-saving tools through an app.

“For most of us,” Palmquist said, “we just don’t know how much water we’re wasting. All we know is that water comes into the house and flows back out. So anything — like an app — that helps educate us is good.”

Contact Dan Nakaso at 408-271-3648. Follow him at Twitter.com/dannakaso.