Maintenance of your water distribution system is extremely important. Your small water system’s source may be of pristine quality and meets drinking water quality standards, but if the distribution system is not maintained or is in a state of disrepair, the water quality may deteriorate before it reaches the water users.
Delivery of Water
The main function of any water distribution system is the delivery of safe drinking water to the consumer. The water source may originate from a well, creek, river, lake or spring. Most water sources require treatment to ensure the water is potable (safe to drink).This removes microorganisms (bacteria, viruses and protozoans), as well as dissolved minerals that may cause illness in humans.
The distribution system is the portion of the water supply system which physically conveys potable water from the treatment plant or source to the users of the system. As the water flows through the distribution system, there are several components that keep the system operational. These include reservoirs, pumping stations, fire hydrants, air valves, gate valves, and piping networks, each of which is described below.
Reservoirs store water for higher demand flows. This could be for fire emergencies or peak domestic flows, such as when people are getting ready for work in the morning and returning home later in the day. The reservoir also acts as a buffer in maintaining the constant flow and pressure of water in the distribution system. For small water systems, pneumatic tanks are typically used instead of large reservoirs as they may be capable of supplying and keeping up with water demand (depending on the size of the water system).
These tanks and reservoirs are generally not sized to provide fire flow. From a public health perspective, the minimum storage should be equal to the average daily consumption or the storage volume calculated to meet CT disinfection requirements (whichever is greater). Further information about disinfection and the CT concept is found within the Treatment web page of this website. A pressure switch regulates the amount of water to be stored in order to maintain constant pressure in the distribution system. A loss of pressure could permit backflow and the introduction of contaminants in the water supply.
Pumping stations are added to the distribution system to maintain pressure and to deliver water to uphill areas and reservoirs.
Air valves are devices that allow air to be introduced into the distribution pipe when a vacuum may be created. A vacuum can potentially damage the pipe or stop the water and should be avoided. The air valves are located at high points in the distribution system.
Gate valves are added throughout the distribution system, so sections can be isolated for work and the water flow can be throttled for pipeline (water main) repair. They are a type of valve that uses a flow control element shaped like a sliding gate to block flow, often used as isolation valves.
Pipe networks’ efficiency is altered by both the materials used and the layout. Pipe material is crucial for efficient water distribution. The smoother the interior of the pipe, such as with PVC pipes and ductile iron, the less friction there is. Similarly, the less twists and turns in the pipe, the more efficient the water delivery.