A leaking water valve in a toilet when you are using a blue-colored toilet tank/bowl cleaning system (such as drop-in pellets or a hanging bottle in the tank) can cause blue water to appear in other parts of your building/home. This usually happens when the toilet is upstairs and the water supply has been shut off for some reason.

Another cause of blue water is extreme copper plumbing corrosion. If this is happening, the water will usually have a bluish-green tint and/or will leave a bluish-green stain on porcelain if the water drips from a faucet. This copper corrosion can be caused by your electrical system being grounded to your water pipes, especially if you have a mixture of pipe materials (e.g. some copper and some galvanized steel).

If the blue color is only in the hot water, it may be due to the temperature setting on the hot water heater being set too high. If you have a hot water circulation system, the return line may be too small, or the water may be pumped too fast for your pipe size, or it may be installed incorrectly.

Blue water can also be caused by dezincification of inexpensive bronze alloys found in valves, water pumps, and water pump parts. This problem can occur in high-rise buildings and large industrial properties where the water is pumped to storage tanks.

If you are not sure if the blue water is due to some plumbing defect within your plumbing system, check the water supply by taking a large white bowl or bucket and going to the water faucet (hose bib) at the front of your house, apartment, or business. This faucet is usually near the main water shut-off valve for the property (in the water box with the meter). Turn the water on wide-open and run it for a full two minutes. Check your watch - two minutes is a long time. After two minutes, fill the bucket or bowl with water. If the water is clear at this front faucet, your plumbing is likely causing the problem, and you should consult a plumber. Some copper corrosion problems can be very complex and may require consulting a corrosion expert. References for corrosion experts can be found in The Blue Book of Building and Construction under corrosion proofing.

If the water at the front tap is discolored after running for two minutes, the problem is likely coming from the Water Board's distribution system, and you should contact the Water Board at 267-3128. If you call after hours, please leave a message that includes your name, address, telephone number, and a brief description of your problem or request. We will return your call at the earliest opportunity.