FAQs

Water main flushing is the process of cleaning or " scouring " the interior of the water distribution mains ( pipes ) by sending a rapid flow of water through the mains. Distribution mains convey water to homes, businesses and hydrants in your neighborhood. In general, distribution mains are supplied with water by larger transmission lines, reservoirs, wells and/ or pumping stations.

Flushing helps maintain water quality. The water entering distribution mains is of very high quality; however , water quality can deteriorate in distribution mains if the mains are not properly managed. This is why flushing is important. Flushing maintains water quality in several ways. First, flushing removes sediments from the mains. These sediments mostly include iron and manganese. Iron sediment results from corrosion of iron pipes and valves used in the distribution system. Other iron sediments result from the change of dissolved iron, which occurs naturally in our water, into sediment form. This occurs in the presence of chlorine and oxygen under certain low flow conditions. Dissolved manganese also occurs naturally in our water and it can be changed into sediments as with iron. Although iron and manganese do not pose health concerns, they can degrade the " acceptability " of the water through affecting the taste, clarity, and color of the water. In addition, sediments can shield micro-organisms from the disinfecting power of chlorine. Therefore, such sediments could contribute to the growth of micro-organisms within distribution mains. Finally, flushing helps remove " stale " water. Much of our distribution is designed with " loops " or interconnected grids, which keep water constantly moving around. However, some areas have dead-ends where water moves slowly and sits for longer periods of time. Such dead-end mains need to be flushed to ensure the presence of fresh water with sufficient dissolved oxygen, disinfectant levels and an acceptable taste and smell.

Edinburgh Water Utilities distribution crews will be operating water valves and hydrants. The water flow will be measured and the chlorine in the water will be neutralized. For a few minutes following flushing, some sediment might get into your home's plumbing. If this happens, please be patient and allow your cold water to run for a few minutes at full velocity. It is recommended to turn the cold water on in the bathtub and let it run until the water is clear. It is not recommended to use a faucet with an aerator as it could get clogged by sediment. During this time, you should avoid using hot water to prevent sediments getting into your hot water heater. Remember that flushing is aimed at maintaining long-term water quality, but it could result in some short-term deterioration. If you know about or see flushing operations in your neighborhood , you would be well advised to not use any water during the flushing period.

The Edinburgh Water Utilities flush all distribution mains twice every year. Starting in the spring ( April ) and in the fall ( September )

Depending on the location, the water may be handled in several different methods : flushed water can be released directly into a sanitary sewer where it would flow to the wastewater treatment plant, water could be released onto streets that have storm drains, water could be discharged to wooded areas or open fields, roadside ditches.

The amount of water used to flush a particular section of pipe depends on a lot of factors, such as water main size, system pressure, the amount of accumulated sediment in the main and the ability to safely dispose of the water. In general, the Edinburgh Water Utilities tries to exchange the water in the main at least three times and at a high velocity to remove any accumulated sediment.