An Early Cold Snap and WSSC aging Pipes

A colder-than-average December is triggering an increase in water main breaks and leaks across Montgomery and Prince George’s counties. The Potomac River temperature is a powerful predictor of water main breaks and leaks. As the river temperature drops, water main breaks/leaks increase, as shown in the chart below.

from WSSC

Between November 26 and Tuesday, the river temperature dropped about 17 degrees from 49 to 32 degrees, triggering a significant uptick in the number of water main breaks and leaks. WSSC Water has experienced 293 breaks/leaks since November 26. 

There is a direct connection between dropping water temperatures in the Potomac River and the increase in water main breaks.  According to the WSSC, they typically see an increase in breaks a few days after the Potomac River temperature hits a new low as the colder water hits the distribution system. The dropping water temperature can “shock” water mains, and though the pipes become accustomed to the cold water; whenever water temperatures hit a new low, there follows a spike in breaks.

On average, WSSC crews repair more than 1,800 water main breaks and leaks each year, with the vast majority of them, approximately 1,200, occurring between November and February. WSSC has already repaired approximately 300 breaks since November this year.  Last winter as seen below, the total number of breaks was above average. There is a large percentage of the distribution system that is quite old.

WSSC Water spends approximately $17 million each year for emergency water main repairs alone, with about $10 million spent November through February. During a typical year, WSSC Water crews repair more than 1,800 water main breaks and leaks, approximately 65 % of which (1,152) occur between November and February. 

Aging infrastructure is a critical factor in breaks and leaks. The older pipes are “shocked” by the colder water, causing them to break. Approximately 42% of the water mains in WSSC Water’s system are more than 50 years old. 

During a typical year, WSSC Water crews repair nearly 1,800 water main breaks and leaks, approximately 63% of which (1,127) occur between November and February. 

 

WSSC Water asks for patience, during the busy winter months. All water main breaks and leaks are inspected and prioritized for repair, taking into account the damage being caused, the safety of the area and the number of customers impacted. With the escalating number of water main breaks, response time can be delayed due to the limited number of crews working across the 1,000-square-mile service area. 

According to WSSC a leak that is not causing damage can be left running to ensure customers have water service until a crew is available to make repairs. Water mains in the WSSC Water distribution system range from three inches to 96 inches in diameter. WSSC Water’s emergency water main break and leak repair costs have increased significantly in recent years. In FY 25, WSSC Water spent $33 million responding to 2,259 breaks and leaks, with $22 million spent between November and February, the four busiest winter months: 

• FY 25: $33 million | 2,259 breaks and leaks
• FY 24: $20 million | 1,697 breaks and leaks
• FY 23: $17 million | 1,566 breaks and leaks

While emergency repairs address immediate service needs, areas experiencing repeated water main breaks will be addressed through WSSC Water’s Capital Improvements Program (CIP), which focuses on long-term system reliability and infrastructure renewal. The Fiscal Years 2026-2031 CIP is $4.8 billion. 

WSSC Water, serving 1.9 million customers in Prince George’s and Montgomery counties, maintains nearly 6,000 miles of water mains covering a 1,000-square-mile area. With such an extensive, aging distribution system spanning the two counties, WSSC Water encourages customers to report water main breaks and leaks as quickly as possible.

Responding to these emergencies has slowed WSSC’s ability to replace the older water mains and WSSC continues to work to update the system. WSSC serves 1.9 million customers in Prince George’s and Montgomery counties, with approximately 5,900 miles of water mains covering a 1,000-square-mile area. With such an extensive, aging distribution system spanning the two counties it is hard to keep up and very difficult to move forward to reduce the age of the system of pipes.