Environmental Services
Water Main Cleaning and Lining
What are Water Mains? | ||
| Water Mains are pipes that carry drinking water around the County to people's homes and businesses. The Water, Sewer and Streets (WSS) Bureau rehabilitates a portion of the County’s water mains every year. WSS uses several criteria to determine which water mains need to be cleaned each year, such as fire flow testing, system modeling, age of mains, and number of main breaks. Residents are notified by letter in advance of any water main work in their neighborhood. | ||
Why Clean Water Mains? | ||
| Cleaning and lining drinking water mains can prolong the life span of the pipe, for less than the cost of replacing the pipe, and with fewer service disruptions to residents. Instead of completely replacing the water main, it is possible to rehabilitate the pipe if it is in good condition. Corrosion deposits, known as tubercles, build up naturally over time in unlined iron water main pipes. The build-up does not normally affect the quality of the water, but it does reduce the effective diameter of the pipes, which decreases the capacity of the pipes. The buildup can also affect the pressure in the pipes. |  | |
Cleaning Process | This tool is pulled through the pipe to remove corrosion. | |
A trenchless pipe rehabilitation method called Mechanical Cleaning and Cement-Mortar Lining is used. Trenchless methods involve only opening holes in the road at the ends of the pipe segment, instead of cutting the road open along the entire length of the water main. Trenchless methods are less disruptive to traffic flow through the work area. |  | |
| This machine sprays the mortar coating on the interior of the pipe, resulting in a smooth finish. | |
Temporary Water Service | ||
| When a water main is out of service during the cleaning and lining process, temporary service lines are used to provide water to the affected area. These temporary lines are disinfected and tested just like regular water mains before being placed in service. Residents will experience only a short disruption of water service during the installation and removal of the temporary lines. Temporary service lines and newly lined water mains must be flushed before putting them in service. Flushing is performed to make sure that all water lines are free from any debris that may have entered the system. While this results in some amount of lost water, the overall quantity is small and allows us to maintain a high water quality throughout the cleaning and lining process. The water is dechlorinated before it is discharged to the storm sewer. |
Temporary water service, including temporary fire hydrants, is installed during the project to provide residents with water service and to ensure adequate fire protection at all times. | |
