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Is Your Water Cloudy?

When cloudy water comes out of our kitchen or bathroom tap, it’s understandable to wonder whether it is safe to drink or use. Most of the time, cloudy water is the result of some activity in the water distribution system that stirs up the calcium carbonate that has settled in the pipes over time.

This calcium carbonate is a result of the softening process that takes place at our water treatment plants. It is not a contaminant and it is not harmful. As a matter of fact, it is the main ingredient in many antacid tablets.

  • Activities that can create cloudy water

    Sometimes it is caused by water main breaks. Other times, it is caused by the opening and closing of valves in the water distribution system when work is being performed to improve the system. Mostly, cloudy water occurs when firefighters perform maintenance on hydrants and open the hydrants and flush them during the day.

  • Length of time water can remain cloudy

    Usually the cloudy water clears within minutes. Sometimes, it may take several hours. Typically, the activity that caused the cloudy water is short lived and creates a "slug" of cloudy water that moves through the pipes as the water is used by customers. The more use, the faster the slug moves though the system and through your residence.

    By opening the taps in your home or flushing your toilets, the cloudy water moves through the plumbing in the home and clears up.

  • Assurances the water is not contaminated

    The water treated at all Miami-Dade Water & Sewer Department water treatment plants meets Federal, State and Local drinking water standards. As the water travels though the distribution system, two barriers consistently ensure that the water continues to meet standards after it leaves the treatment plant.

    These two barriers are water pressure and the maintenance of a residual disinfectant. Both of these barriers are mandated by the regulations that are in place to protect our drinking water.

    • Water pressure: A minimum of 20 pounds per square inch (psi) must be maintained throughout the water distribution system at all times (Florida Administrative Code, Chapter 62-555.350(7)). Water pressure is continuously monitored by treatment plant operators. Typically, normal pressures in the distribution system range between 40 and 60 psi. Maintaining a minimum pressure of 20 psi prevents contaminants from entering the pipes from the outside. This is especially important when a main break occurs. The pressure inside the pipe will cause the water to flow out from the pipe instead of allowing groundwater to flow into it. If the water pressure should fall below 20 psi, a precautionary boil water order would be issued.
    • Residual disinfectant: A minimum of 0.2 mg/L of free chlorine or 0.6 mg/L of combined chlorine must be maintained throughout the water distribution system at all times (Florida Administrative Code, Chapter 62-555.350(6)). Residuals are monitored daily both at the treatment plant and in the water distribution system in accordance with regulations. The presence of the residual disinfectant will counteract the introduction of potential contamination that could result from a reduction of pressure in the pipes.

    It is important to note that the very thing that makes our water cloudy (calcium carbonate) is present in the pipes all of the time. We mentioned earlier that calcium carbonate is not a contaminant and is not harmful. The cloudy condition is merely caused by the suspension of this very fine material when changes in velocity or pressure occur in the distribution system. Thus, cloudy water is not likely to be an indication of contaminated water in our closed and pressurized water distribution system.

  • What to do when tap water comes out cloudy

    First, let the water run for a few minutes. If it does not clear up, wait about 30 minutes and try it again. If it continues to come out cloudy, you may call the WASD water quality lab that serves your area. If the water does not clear on its own, the lab may schedule a fire hydrant flush between 11 p.m. and 5 a.m. The lab may also dispatch a technician to sample the water and confirm that water quality has returned to normal.