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Water Supply FAQs

Frequently asked Questions about Drinking Water Supply


  1. My water supply was off recently and the water is discoloured coming from the tap. Why?
    When the water supply has been switched off to carry out repairs to bursts etc., some sediment can become dislodged from the water pipes during the switching back on of the supply. If you run the water for a short time it will run clear
  2. My water supply was off recently and the water appears cloudy or white coming from the tap. Why?
    This is quite a common occurrence when a watermain has been opened to repair bursts etc., air enters the pipe network and gives the water a milky/cloudy appearance when it comes from the tap. If you leave the water to settle in a glass you will see that the air quickly leaves and the water is as clear as normal.
  3. My water is off at the moment, can I use my central heating system or appliances?
    If heating systems and appliances are plumbed correctly there's no problem running them during or after a water disruption. In South Dublin we only permit indirect plumbing, i.e. the only thing plumbed directly off the mains is the kitchen tap and everything else should be independent or supplied via a storage tank including your heating. During a water disruption the supply to your kitchen tap will stop, but all the water supply to all other water points in your property should continue as these should all be plumbed via your storage tank. We advise that you use water sparingly during any service disruption as this will ensure you have enough water in your storage tank for at least 24 hours normal usage
  4. The water supply was turned back on but I still don’t have water?
    This can be due to the following:

    House Location
    Depending on a person’s house location, it can take a number of hours for the network to fully recharge. What happens when water is restricted is that the network itself empties (empty pipes) as consumers continue to use the supply, and individual household storage tanks are also used. When water is restored, the network refills including what is now the empty or partially empty storage tanks of individual households refilling. Consequently, depending on where within the network your house may be, it can take a period of time to have full service restored. When it does return, your attic storage will also fill and be replenished
  5. My water was off recently and although water has come back to the cold tap in the kitchen there is no water in other taps in the house. AIRLOCKS?
    This occurs in some plumbing systems after a water shutdown. It is an airlock in your system and you may need to engage a plumber to eliminate it. SDCC endeavour to keep service disruptions to a minimum but do not maintain internal plumbing systems

    Advice on Getting Rid of Airlocks
    Following a disruption to Water Supply some households may get airlocks in their internal plumbing system. The airlock is generally in the hot water system and most likely the result of faulty internal plumbing. This is what to do if you get an airlock:-

    Firstly make sure all hot taps in the house are in the closed position. Then either proceed with option 1 or 2. Step 3 applies to both.

    If you have a problem or concern, contact a qualified plumber for advice.

    1. If the hot and cold taps in the kitchen are separate i.e. not combined in a mixer tap, the hot tap should be turned on. If there is an airlock, no water will come from the hot tap. A short length of hose should be used to connect the hot and cold taps in the kitchen only. Turning on the cold tap will result in the cold water being forced through the hot water system and this will force the air which is causing the airlock back into the water tank in the attic.


    2. If there is a mixer tap in the kitchen, the hot tap should be turned on. With a cloth in your hand (to help reduce water squirting out) block the mixer tap and turn on the cold water tap gently. This should force the cold water back through the hot water system, forcing the air into the water tank in the attic. Care should be exercised when doing this in case of accidental scalding with hot water.
    3. Let this run for 1 – 2 minutes, then turn off the cold tap and let the hot tap run for 1 – 2 minutes to confirm that the air lock is cleared. If the air lock is not cleared, repeat the procedure one or two times more. If this is not successful, contact a plumber and get them to correct the problem. In rare cases the cold water taps in wash hand basins or the bath may also be air locked. This procedure will also work for them, but is more difficult as a long length of hose is necessary from the kitchen cold tap to the nearest wash hand basin or bath tap.
    4. Why can't we be informed of all water shutdowns in advance?
      In most cases loss of water supply is for very short periods of time. SDCC are not usually in a position to inform of shutdowns in advance as they usually are of an emergency nature, i.e. burst mains, and our priority is to attend to the problem and repair the burst as quickly as possible. Notifications of all major planned shutdowns, and of major emergency shuts to repair bursts, are given in the national and local media and on the Council’s website www.sdcc.ie and Social Media Pages.

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