A common problem in household water systems is that of water staining basins, sinks and toilet bowls, and even laundry, dishes and glassware. Water stains may either be a blue or green color, or sometimes dripping water leaves a red/brown stain on sinks and clothing. The color of the stain will depend on the contaminant that is present in the water. While the problem of color staining does not pose any direct health issues, it can be costly to replace damaged fixtures and fittings, or clothing ruined by staining. Staining is very often also associated with other problems, such as sediment, turbidity, or taste and odor issues in drinking water, which can be both unpleasant, and cause further damage to fittings and fixtures.
Blue-green stains on porcelain fixtures in the bathroom, toilet, or kitchen usually indicate water that is highly corrosive, and is corroding copper pipes. This corrosive action can increase the levels of copper and lead in drinking water, which can pose a health risk if levels of these metals are high. Highly corrosive water can also cause problems with household plumbing and pipes, so if you suspect that this may be the problem, it is best to have it investigated by your water provider or to have a plumber look into it further. Stains on bathroom porcelain can be removed with a solution of baking soda, or with ammonia, but unless you tackle the root of the problem, they will simply re-occur very quickly. Very corrosive water is generally acidic (low pH value) and consequently the corrosive action can only be reduced by neutralizing the water. This can be achieved with chemical injection of softening agents into the water, or by fitting a neutralizing filter to increase the pH of your water to more acceptable levels.
Reddish-brown stains on fixtures and fittings are indicative of high levels of iron in water. This is caused by rust in the water, usually as a result of corrosion of galvanized iron, cast iron, or steel pipes. Rust stains can stain both porcelain fixtures and clothing and linen that is being washed in the laundry, but besides from causing these unpleasant problems, it doesn't pose a direct health risk in drinking water. Rust stains on porcelain fixtures can be removed with vinegar or lemon juice, but this will have to be done on a weekly basis to prevent the stains from becoming unsightly once again. Better still tackle the problem head-on to prevent the stains from reoccurring by making use of an appropriate water treatment option. There are a number of options for treating water that has unacceptable levels of iron: phosphate treatment; iron exchange; greensand filtration; or by chlorination to oxidize the iron, followed by filtration.
Manganese is very similar – and often found together with – iron in water. The presence of even low levels of manganese in water can cause dark brown to black stains on clothing and linen when laundry is washed. Manganese can be removed from household water by using the same methods as used for iron – by installing a water softening system, or a filter capable of removing manganese and iron.