Taste, odor, color and sediment in drinking water

Taste and odor;  Discoloration; ParticlesDezincification of brass;  PDF of paper brochure

TASTE AND ODOR SOURCES

The Orange Water and Sewer Authority (OWASA) treats water from the Cane Creek, University Lake, and Quarry reservoirs. Drinking water can naturally develop tastes and odors. The most common of these in our area are a chemical/chlorine or earthy/musty taste and odor.

TYPES OF TASTE AND ODORS

Chemical/Chlorine

OWASA disinfects the drinking water with chlorine and chloramines to ensure protection against contaminants throughout the distribution system and in your home/business. Chloramines have little to no odor and are a compound made from chlorine and ammonia. Routine samples are collected and analyzed throughout the system to ensure disinfectant levels are at or below our stringent target level.

However, at times customers may notice a chemical or chlorine taste and odor. This type of odor is often an indicator that the disinfectant is effectively working to remove bacteria and organics in your pipes. As the disinfectant reacts with bacteria and organics, it breaks down into more odorous forms of chlorine compounds.

This chemical or chlorine taste and odor is most often reported in March and early April when OWASA temporarily switches disinfectants from chloramines, that have limited chlorine taste and odors, to chlorine (sodium hypochlorite) which is more odorous. OWASA makes this annual switch in March as a maintenance activity to optimize the water quality of the distribution system to:

  • Remove any biofilm and bacteria from the water distribution system pipes;
  • Reduce the formation of nitrates and nitrites (nitrification);

This maintenance process is recommended by the US Environmental Protection Agency and NC Department of Environmental Quality. 

Link to 2017 notice of chlorine disinfection in March

What can you do?

Please be aware that in March and early April, chlorine taste and odor are normal because of an annual change in our disinfection process. The water is safe to consume.

If you would like to remove the chlorine from the drinking water to improve its taste and odor, you may do so with several methods, including:

  • filtering the water with an activated carbon filter such as a Brita pitcher filter,
  • letting the water sit out in the refrigerator for a day or so,
  • boiling the water for one minute to cause the chlorine to evaporate,
  • adding a few lemon slices to a pitcher of water. The lemon has ascorbic acid, which will naturally dechlorinate the drinking water. 

If you are concerned about your water quality or wish to report a taste and odor issue, please contact our Water Treatment Plant Laboratory staff at 919-537-4228 or wtplaboratory@owasa.org

The Laboratory staff at our Jones Ferry Road Water Treatment Plant.

Left to right: Robert Herring; Katie Harrold, Supervisor; Chris Gibbons. 

Earthy/Musty

An earthy or musty taste or smell, particularly in warmer weather, may be a result of elevated levels of organic matter in our reservoirs.

During the fall, reservoir water “turns over.” As the surface of the lakes cools to the same temperature as the bottom waters, mixing of the water layers occurs. This stirs up sediment that contains organic matter. Additionally, algae thrive at different times of the year in our reservoirs. Although our treatment process is able to remove the algae and organic matter, some organic compounds may be left behind. These compounds are harmless, but are noticeable to some people at very small levels.

What can you do?

OWASA regularly monitors for taste and odor in our water. Chemicals are used in our treatment process to help remove organic matter from reservoir water and are adjusted as needed. If you are concerned about your water quality or wish report a taste and odor issue, please contact our Water Treatment Plant Laboratory staff at 919-537-4228 or wtplaboratory@owasa.org

Other Odors

Odors commonly come from the sink drain and not the water from the faucet. The plumbing beneath your sink can collect debris over time and create an odor. If you smell an odor, fill a clean glass halfway with tap water and smell the water in a separate room or outdoors. If the odor is no longer present, the odor is likely from the plumbing beneath your sink. We recommend pouring bleach or a disinfection product down your drain to remove any debris and odor. If the odor is not from the sink or the problem persists, please contact our Water Treatment Plant Laboratory staff at 919-537-4228 or wtplaboratory@owasa.org

Many floor drains and sinks have a p-trap (a plumbing device that blocks air flow with a water barrier) to prevent odors in drains and sewers from rising through the drain into a home or business.  If a sink or drain is not used for a long time, the p-trap may go dry and allow odors to enter a building.  To refill a p-trap, pour water down a floor drain or run water in a sink. Please click here for more information about p-traps. 

DISCOLORATION AND SEDIMENT SOURCES

On rare occasions, tap water may become discolored or you may notice sediments. The discoloration can range from cloudy to light yellow to dark brown color. At times, customers have reported noticing black or white particles.

TYPES OF DISCOLORATION

Cloudy or Milky

Milky or cloudy water is often caused by air bubbles in the water system. Cloudiness and air bubbles do not present a health risk. Typically air enters the distribution system because of  changes in the water temperature or during construction/repairs. If you notice cloudy water, fill a glass with tap water and let it sit for a few minutes. The cloudiness and air bubbles should naturally disappear. Flushing your cold water tap for 5-10 minutes should clear up the cloudy water. If the cloudy water does not disappear after 10 minutes of flushing, please contact our Water Treatment Plant Laboratory staff at 919-537-4228 or wtplaboratory@owasa.org

 

Yellow to Dark Brown

Water heaters are a common source of yellow or brown discolored water.  If the discoloration is only in the hot water, accumulated sediments in the bottom of the hot water tank are likely the source.  We recommend flushing water heaters annually following the manufacturer’s instructions or contacting a licensed plumber for advice.

If your water is yellow or brown or rusty in color, the cause is likely iron or manganese sediments that have settled in the water pipes over time.  Iron and manganese are both naturally present in our reservoirs. In addition, iron pipes in our distribution system can be a source of iron discoloration.  Maintenance and repair work, nearby construction, or flushing of water pipes (by releasing water from a hydrant or other release point) may stir up these particles and cause discoloration. Iron and manganese in drinking water are not a health risk.

Discoloration is usually temporary and should disappear after water is flushed from the distribution system or your home plumbing. OWASA recommends not drinking tap water if it is discolored. In addition, do not wash clothes when water appears rusty, because the rust can stain fabric. Flushing your cold water tap for 5-10 minutes should clear up discolored water. If the color does not disappear after 10 minutes of flushing, please contact our Water Treatment Plant Laboratory staff at 919-537-4228 or wtplaboratory@owasa.org

Green/Blue

If your water is green or greenish blue in color, this may indicate deterioration of copper plumbing (e.g., in a water fountain). OWASA recommends consulting with a plumber to find the source of deterioration and a possible solution.  

Black Sediment or Particles

Black particles are often precipitated iron and manganese in water.  Iron and manganese are both naturally present in our reservoirs. In addition, iron pipes in our distribution system can be a source of these particles.  Maintenance and repair work, nearby construction, or flushing of water pipes (by releasing water from a hydrant or other release point) may stir up these particles. Iron and manganese in drinking water are not a health risk.

Another common cause of black particles in tap water is the disintegration of rubber materials used in plumbing systems. Sources of the rubber materials are typically:

  • toilet flappers,
  • rubber washers/o-rings,
  • membranes in thermal expansion tanks on hot water heaters, and
  • liners disintegrating from the inside of flexible hoses which could be on water heaters or underneath sinks.

In addition, the use of chloramines as a disinfectant can contribute to the disintegration of rubber materials. OWASA recommends replacing the deteriorating rubber (such as a toilet flapper) with one that is resistant to chloramines (which should be clearly advertised on the label).

White Particles

White particle buildup comes from a variety of sources and is most commonly originating from the hot water system. Typically, this buildup is either calcium carbonate or from a type of brass corrosion called dezincification (more information is below).

Dissolved calcium is naturally found in our drinking water and can change to calcium carbonate in hot water heaters. Over time, calcium carbonate may accumulate at the bottom of the hot water heater and collect in your faucet aerators. OWASA recommends periodically flushing your hot water heater to remove any sediment buildup.

DEZINCIFICATION OF BRASS 

Dezincification is an electrochemical process in which zinc, a component of brass, is released from low quality brass fittings. When zinc is released from brass, it often forms zinc oxide, which may be visible as white or gray sediment in a plumbing component. This sediment may slow or block the flow of water.  The loss of zinc may also weaken the brass fitting or result in leaks.

Recirculating hot water heater systems may be susceptible to brass dezincification because hot water is continuously in contact with the plumbing components, and heat accelerates the buildup of zinc oxide (white or gray sediment). OWASA recommends that you get specific advice from a licensed plumber based on the type of heating/plumbing equipment you have.

Under current national codes, brass fittings in plumbing equipment are required to have a low level of zinc to limit the potential for dezincification. Fittings made with dezincification resistant (DZR) brass are available.

The direct connection of dissimilar metals (e.g., brass and steel or brass and copper) can accelerate dezincification.  Plumbers use fittings called dielectric unions to separate dissimilar metals and minimize the potential for galvanic corrosion.

Black/Grey or Pink/Orange Slime

Bacteria, mold and fungi can grow on surfaces where water is exposed to air (e.g., in a toilet bowl, around sinks or in showers). They may appear black or pink in color.  These growths are produced by airborne fungal spores or bacteria and are not originated from drinking water. OWASA recommends periodically scrubbing and cleaning the toilet, shower, or sink with cleaning products containing bleach.

For concise information on taste, odor, color and sediment in water, please click here.

FOR MORE INFORMATION

Which water pipes are OWASA’s, and which are privately owned and maintained?

Which sewer pipes are OWASA’s, and which are privately owned?

Water expands due to normal operation of a water heater, and what to do about this

What is a p-trap?

Protecting pipes from freezing

Water pressure in plumbing systems; pressure reducing valves

Having a water shut-off valve and marking its location(s) in your plumbing system