Water is often described as tasteless, odorless, and colorless, yet a noticeable flavor from the tap is a common complaint for many people. When water tastes unpleasant, it is a signal that trace elements or compounds are present, altering the neutral flavor profile of pure water. These aesthetic issues arise from several sources, including chemicals added during municipal treatment, naturally occurring geological minerals, and materials encountered within the home’s plumbing system. Understanding the origin of the unwelcome flavor is the first step toward resolving the issue and enjoying clean-tasting water.
Tastes Resulting from Municipal Disinfection
A sharp, chemical taste often likened to a swimming pool is directly linked to the disinfectants used in public water systems. Municipal water treatment facilities add chlorine or chloramine to eliminate harmful bacteria and pathogens. This residual is maintained throughout the distribution system to prevent contamination.
Free chlorine, the most common disinfectant, imparts a distinct bleach-like flavor noticeable even at low concentrations. When ammonia is added to chlorine, it forms chloramine, a more stable compound that persists longer in the pipe network. Chloramine typically results in a more medicinal or chemical flavor. Furthermore, chlorine can react with naturally occurring organic matter in the source water to form byproducts like trihalomethanes, which also contribute to an undesirable aftertaste.
Natural Minerals That Affect Water Taste
Geological elements in the source water, particularly in groundwater supplies and private wells, can significantly affect the flavor profile. One of the most recognizable off-flavors is the “rotten egg” smell and taste, which is caused by hydrogen sulfide gas. This gas is often produced by sulfur bacteria feeding on sulfur compounds in the water, or it can be a byproduct of chemical reactions with the magnesium anode rod inside a hot water heater.
A metallic or bitter flavor is often an indicator of high concentrations of dissolved iron and manganese. Iron can impart a rust-like taste and may cause reddish-brown staining on fixtures. Manganese, which frequently co-occurs with iron, contributes a bitter metallic note and leads to black or brown stains. Hard water, characterized by high levels of dissolved calcium and magnesium, may result in a chalky or mineral-like taste. A salty taste can be caused by elevated levels of sodium and chloride, which may occur naturally or from external sources like seawater intrusion.
How Plumbing and Organic Matter Change Water Flavor
The journey water takes from the treatment plant to the tap introduces opportunities for flavor alteration from plumbing and biological factors. A metallic taste can also arise from the corrosion of household plumbing materials, such as copper, galvanized steel, or brass. As these pipes age, microscopic particles of metals, including copper or zinc, can leach into the water, resulting in a metallic tang. Hot water can accelerate this leaching process and often tastes more metallic or bitter than cold water.
New plumbing materials, especially plastic pipes like PEX, can temporarily release organic chemicals from the manufacturing process. This can cause the water to have a temporary “stale,” “fruity plastic,” or “waxy plastic citrus” taste. An earthy or musty flavor, sometimes described as tasting like dirt or mold, is caused by organic matter. These flavors are linked to naturally occurring compounds like geosmin and methylisoborneol (MIB), produced by algae and certain bacteria in the source water. Tannins, organic compounds from decaying vegetation and peaty soil, can leach into the water, giving it a slightly tart or earthy flavor.
Practical Steps to Identify and Resolve Bad Water Taste
Resolving a bad water taste begins with a simple sensory test to identify the source. Check if the off-flavor is present in both hot and cold water; a problem localized to the hot tap often points to the water heater. If the taste is consistent across all cold water taps, the issue is likely rooted in the water source, main plumbing, or municipal treatment process. Professional water testing confirms the exact contaminants and their concentrations, guiding the choice of treatment.
For the taste of chlorine, let a pitcher of water sit uncovered in the refrigerator for a few hours; this allows the volatile chlorine gas to dissipate. Chemical and organic tastes, such as chlorine, geosmin, and tannins, are effectively removed by activated carbon filtration systems. To address metallic tastes from pipe corrosion, running the cold water tap for a few minutes each morning can flush out water that has been sitting stagnant overnight. For high concentrations of minerals like iron, manganese, or sodium, a reverse osmosis system or a water softener is needed to physically remove or chemically manage the dissolved solids.