New York, NY —

The city is sending out nearly 15,000 warning letters this week, threatening to impose liens on property owners who haven't paid their old water bills.

That comes on top of an ad campaign, and a 92-page supplement in the Daily News yesterday, listing every property in the city with outstanding debt.

In all, home owners owe the city more than $160 million in water debt.

In the past, the city couldn't easily collect that debt unless an owner also had outstanding property taxes. But the laws were changed, and a city spokesman says most water debts are likely to be resolved by home owners before the 90-day deadline.

After that, however, the city will sell all remaining debt to private collectors. And if they can't resolve the debt, they're allowed to begin foreclosure proceedings on someone's home.

For WNYC, I'm Arun Venugopal.