Before a drop of treated water in California ever reaches a consumer’s faucet, about 8% of it has already been wasted due to leaks in the delivery system. Nationally, the waste is even higher, at 17%. This represents an untapped opportunity for water savings, according to a study from the University of California, Davis.

The study, published in the journal Environmental Research Letters, is the first large-scale assessment of utility-level water loss in the United States.