The nation’s plumbing has sprung a leak that requires a $1 trillion repair job if Americans want to keep flushing their toilets and drinking clean water in years to come, the American Water Works Association said in a report issued Monday.

Unless that investment in replacing old water and sewer systems begins soon, a plague of leaks and service disruptions that already has begun in some places — notably the District and suburban Maryland — will continue to spread through the more than 1 million miles of pipelines, the report said. Delaying action now will result in higher costs later, an expense that is expected to cause water bills to soar in the coming decades.

The report comes two months after a similar study by the American Society of Civil Engineers concluded it was necessary to spend an additional $9.4 billion per year between now and 2020. Nationwide, an estimated 1.7 trillion gallons of water leaks from pipes each year before it can be put to use. About 900 billion gallons of raw sewage flows into waterways.