Mandatory water restrictions in San Diego begin on June 1, which means homeowners are looking to cut back on their water bills. You may have a water leak you don't even know about, but a new product can help you detect a leak in just five seconds.

North County inventor John Schommer says conserving water starts with your toilet.

"I think you'll find that up to 15 percent of all toilets leak all the time," Schommer said.

John invented Miser-Blue, a product he says can detect toilet leaks in five seconds or less.

"We take the Miser-Blue into the bowl and every streak is a leak," he said.

John once used Miser-Blue to test 450 toilets at an apartment complex and found 257 of those toilets were leaking - up to 78,000 gallons of water each per year.

In an era where every drop counts water departments throughout California are using Miser-Blue to conduct water audits.

"Several water districts are using it and cities like the City of Long Beach, Santa Cruz, Santa Barbara," he said.

Not satisfied with Miser-Blue alone, John went on to invent his own replacement toilet tank flapper with an adjustable dial to save you even more water. But remember, before you fix a flapper, check and see if your water and money are getting flushed down the toilet.

"It's really that easy and it's really that important," he said.

John says by just repairing one toilet in your house alone, you can save up to 200 gallons of water a day - 10 times the county's 20-gallon challenge.

A bottle of Miser-Blue costs $8.50 and is good for 30 toilet tests.