Shared from the Albemarle County Service Authority Website
What is the black slimy stuff in my toilets/faucets/shower head?
Welcome to the fascinating, but often annoying, world of micro-organisms! If you are experiencing dark gray/black “stains” or slimy residues in a toilet, at a sink faucet, or even on a shower head, the good news is you don’t have a water quality problem, and the water is not harmful. However, we realize this is certainly an aesthetic issue, so we will provide you with some information, and help you to fix the problem.
These residues are the growth of naturally-occurring mildew (a type of fungus), possibly in combination with harmless bacteria, which are commonly seen in our area. The mildew DOES NOT enter your home or business in our water, but any constantly-moist surface, like the ones mentioned above, provide a great place for them to grow. Microscopic mildew spores are present in leaves, soil and mulch, especially when moist. (Note: We see a direct link of complaint calls with areas that are heavily-mulched). The spores enter your home with your normal coming and going, through open windows and doors, on your own hair and clothing, and especially on a pet; you truly will be unable to keep them entirely out of your home. When the spores “find” a moist environment, especially where it is also dark and air flow is limited, they are far more likely to survive, and thrive. These are the normal conditions in toilets, bathrooms in general, and at faucet aerators, but the mildew may also be found inside the water dispenser of a refrigerator, in the drain tube and bucket of a dehumidifier, or beneath the mat in the kitchen sink.
The mildew will not survive in chlorinated drinking water. However, where water stands for any length of time (such as in a toilet, at the mouth of faucet, or on a shower curtain), the residual chlorine disinfectant dissipates to the air, and the mildew growth may occur. Customers who remove the chlorine from their water by use of an activated carbon filter may even be more likely to experience the problem.
So how do I get rid of the growth?
Once established, this mildew may be difficult to eliminate entirely. However, regular and thorough cleaning, accompanied with, or followed by, disinfection with chlorine bleach, is the best means to control the organisms.
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- For toilets, clean the bowl regularly and thoroughly. The mildew will wipe away easily. You may wish to add ¼ cup of bleach to the toilet tank, let stand for 15-20 minutes, and then flush the bowl a couple of times to move the bleached water through the flush ports. Bleach should not be left in the toilet tank for prolonged periods, however, as it will damage the rubber seals and valves inside.
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- You may wish to use a disinfectant product that attaches to the toilet bowl. Products placed in the tank are known to cause damage over time (see above).
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- Use care with any abrasives to avoid scratching a fixture or surface, which will raise the likelihood of mildew growth.
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- For our customers who have a septic system, consideration should always be given to the amount of bleach or other disinfectants that are allowed to enter the system.
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- Make sure shower curtains are always left fully open to dry thoroughly. Spray the curtain with a product that contains bleach or other disinfectant. Leave the exhaust fan on longer than normal, especially in the warm, humid months. If you do not have an exhaust fan, opening a window may make the situation worse if more spores enter the home.
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- Remove sink aerators, reverse-flush them, and use an old toothbrush to clean them. Soak them in a 50/50 bleach/water solution for 20 minutes before returning them to the faucet.
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- If pliers are needed to remove an aerator, pad the aerator with a thin rag so as not to scratch it.
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- A shower head can be soaked in a bleach solution as described above, or may need to be replaced if the growth is extensive.
- Use a cotton swab dipped in a bleach solution to clean inside the water dispenser of a refrigerator; rinse with a water-damp swab. Long-handled swabs may be necessary.
Note: Another form of black staining that can be seen in the water of a home is not microbial in nature, but is due to the chemistry of the water. This is the black staining related to excessive manganese in the water, and can be seen in some private wells in our area. Manganese removal will require a specialized water treatment. You WILL NOT experience this type of staining with the water we deliver to your home or business.
Note: This discussion of mildew above is entirely different from the black stains that may be present on dry wall, plywood, or other inside surfaces where a moisture problem exists, such as in a basement, crawl space, or under vinyl flooring . This is mold of other types, and may possibly be a health concern. The ACSA recommends that you call a mold remediation specialist or a certified home inspector if you require assistance in this area.
What is that pink stuff in my bathroom tub/sink/toilet?
You may have noticed pink-colored “stains” or growths that can develop in moist areas in your home, particularly in the bathroom, and especially in the warm-weather months. You may see these growths around a tub or sink drain, on a folded portion of a shower curtain, in a toilet bowl, or even in your pet’s water dish… and you naturally want to know if there is something wrong with your water.
Most importantly, a pink residue is not a problem with your water quality, and it is not harmful in this situation. It is evidence of a kind of bacteria that can commonly appear and grow in these conditions. The most typical of these bacteria has the scientific name of Serratia marcescens. These bacteria DO NOT enter your home or business in our water, but the constantly-moist surfaces mentioned above provide a great place for them to grow. The bacteria typically come from soil, dust, or mulch, and enter your home as microscopic spores in the air, on your clothing, and especially on a pet. A pink stain or film can even appear during or after construction or remodeling, when dirt and dust containing Serratia are disturbed. The problem is often more noticeable in the summer months when temperatures and humidity are higher, and especially if windows are kept open for any length of time.
The bacteria that lead to the pink growth will not survive in chlorinated drinking water. However, where water stands for any length of time (such as in a toilet, around a drain, or on a shower curtain), the residual chlorine disinfectant dissipates to the air, and the pink color may develop from the spores. Customers who remove the chlorine from their water by use of an activated carbon filter may even be more likely to experience the problem.
How Can I Get Rid of the Stains?
Any pink growth can typically be controlled quite easily through regular and thorough cleaning, accompanied with, or followed by, disinfection with chlorine bleach.
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- Wipe bathtubs, shower walls and curtains, and around drains, in order to dry them, followed by spraying with a product that contains bleach or other disinfectant.
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- For toilets, clean the bowl regularly. You may wish to add ¼ cup of bleach to the toilet tank, let stand for 15-20 minutes, and then flush the bowl a couple of times to fully rinse the disinfectant. Bleach should not be left in the toilet tank for prolonged periods, however, as it will damage the rubber seals and valves inside.
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- You may wish to use a disinfectant product that attaches to the toilet bowl. Products placed in the tank are known to cause damage over time (see above).
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- Use care with any abrasives to avoid scratching a fixture or surface, which will raise the likelihood of bacterial growth.
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- Clean pet water bowls in a similar manner. Leave a bleach solution in the bowl for 15-20 minutes, followed by thorough rinsing.
- For our customers who have a septic system, consideration should always be given to the amount of bleach or other disinfectants that are allowed to enter the system.
Should you have any further questions, please contact Tim Brown at 977-4511, ext. 119, or tbrown@serviceauthority.org
