Pennsylvania environmental officials have put 24 counties including Carbon, Schuylkill, Northampton and Monroe under a drought warning and the rest of the state under a drought watch.

Meager rainfall and high temperatures prompted the Department of Environmental Protection (DEP) to issue the warnings Thursday. DEP Secretary John Hanger says a hot, dry summer has led to steadily declining ground and surface water levels.

A drought warning asks residents to voluntarily reduce water use by 10-15 percent.

DEP said rainfall deficits over the past 90 days are currently as great as 5.6 inches below normal in Somerset County and 5.5 inches in Bucks County.

Other counties under a drought warning include Philadelphia, Allegheny, Lehigh, Lackawanna, Luzerne, Bucks, Montgomery and Washington.

A drought watch is the lowest of three advisory levels and a drought warning is the second-most severe condition. No counties in the state are under a drought emergency.

DEP is sending letters to all water suppliers statewide, notifying them of the need to monitor their supplies and update their drought contingency plans as necessary. It monitors a statewide network of groundwater wells and stream gauges that provide comprehensive data to the state drought coordinator.

DEP offers the following tips for conserving water around the home:

Ÿ Install low-flow plumbing fixtures and aerators on faucets

Ÿ Check for household leaks a leaking toilet can waste up to 200 gallons of water a day

Ÿ Take short showers instead of baths. Kitchen/laundry areas

Ÿ Replace older appliances with high efficiency, front-loading models that use about 30 percent less water and 40-50 percent less energy

Ÿ Run dishwashers and washing machines only with full loads

Ÿ Keep water in the refrigerator to avoid running water from a faucet until it is cold.

The department also offers water conservation recommendations for commercial and industrial users, such as food processors, hotels and motels, schools and colleges, as well as water audit procedures for large water customers. Water conservation tips and drought information can be found online at www.depweb.state.pa.us, keyword: drought.