A high volume of calls to the Philadelphia Water Department and area water companies are a sure sign winter has settled in.

But this year the calls are pouring in because of the extreme cold, according to the department, which supplies drinking water to households in Philadelphia as well as some suburban communities..

"We're getting a lot of calls from customers about frozen pipes," said Laura Copeland, a Water Department spokeswoman.  "I think it's all over the city.  It's not concentrated in any one area."

She said the situation is similar to several years ago, when there was a prolonged cold spell.  The last two winters have been mild by comparison.

Copeland says the department is averaging about 20 calls a day reporting either suspected water main breaks or burst pipes in residences or businesses. Water main breaks are the responsibility of the city.  For example, the department dispatched workers to fix a water main break in Northeast Philadelphia early Tuesday.

"The Philadelphia Water Department has seen a significant increase in call volume over the past couple of weeks related to broken service lines, frozen service lines, and broken water mains," Copeland said in a separate email response. "We are responding as quickly as we can to each call, however, there are delays in our ability to get to every broken water main to make repairs as quickly as customers may want.  We're asking for patience while our crews work in the difficult conditions to make sure water service is restored to all customers that are dealing with a broken water main."

But for residential issues, Copeland said, "customers don't always know that this is their responsibility or they don't know what they need to do."

So the department is trying to educate customers through social media, offering home winterizing tips such as letting a trickle of water run from the tap in a basement sink overnight during extremely cold weather so pipes don't freeze. The first sign of a frozen pipe, by the way, is reduced water flow. If you have a frozen pipe, call a plumber for advice. In the meantime, shutting off the water supply to your home can prevent a frozen pipe from bursting.

But it's not just the city dealing with the issue.

Aqua Pennsylvania said a 30-inch water main broke in West Conshohocken around 6 a.m. Tuesday on Balligomingo Road between Route 476 and Front Street.  Crews shut down the main by 11:30 a.m., reducing water flow for customers in areas including Tredyffrin, Conshohocken, West Conshohocken, Lower Merion, Upper Merion, Cheltenham, Plymouth, Whitemarsh, Springfield and Radnor.

Water pressure was slowly being restored to those areas throughout the day, but about 25 customers in Upper Merion were expected to have no water service until repairs were finished.  The company did not provide an estimate when that might occur.

Meanwhile, New Jersey American Water warned that some customers dealing with frozen pipes might expect some delays.