The rubber and plastic materials used in household appliances and fittings are most likely to blame for the chemical taste of your drinking water. Coffee maker gaskets/seals, tap washers, and hoses fitted to the inlet of washing machines and dishwashers are examples of plastic fittings.
These tastes do not come from the water pipes but are formed within the materials that makeup certain items. These plastic and rubber materials contain phenols and other substances that can produce unpleasant tastes or smells. Low levels of chlorine can also react with these materials to create other taste-causing substances.
Although these substances can create unpleasant tastes in hot drinks they do not pose any known health risks at the levels that are usually detected.
Chemical taste can come from one or more of the following factors:
The pressure of your water supply is somewhat higher at night and when fewer people are using water. This increased pressure can cause expansion in the rubber hoses connected to washing machines and dishwashers. When you turn on a tap on your property, the pressure drops, and the expanded rubber hose collapses, squirting water back into the incoming supply.
Water that’s been in your pipes overnight or when your property is vacant is more likely to have taste-causing substances.
Washers deteriorate over time. Because the “break down” of washers isn’t a continuous process, the taste may fluctuate.
Fixing the chemical taste and smell
Try boiling water in a clean saucepan if you only notice the flavor in hot drinks. If the taste has gone away, it’s most likely due to a failing gasket that seals the components inside the coffee maker. This is most noticeable with new coffee makers. If the coffee maker is new, the problem may go away with time. Using new water each time may keep the flavor to a minimum. If the problem persists, you should contact the manufacturer.
Washing machines and dishwashers:
When water pressure increases it can cause the flexi-hose to expand– when the pressure is released, the hose collapses squirting water back into the incoming supply. This water can then mix with your drinking water. To avoid this, disconnect the flexi-hose by turning of the valve that supplies water to your washing machine when it’s not in use. If the valve is difficult to reach, you may want to hire a plumber to relocate it or install a check-valve to prevent water from entering your supply pipe.
The washer in your taps can cause unpleasant tastes or smells in your drinking water. If there’s a second tap in your home, try using the water for it. If no taste or smell is noticeable the cause is likely the tap washer in the original tap. If there aren’t any other taps available, run the tap for a few minutes before tasting it.
Other hoses and fittings:
Flexible or braided hoses and other rubber-like materials are used in many modern kitchen faucet fittings. Some of these fits can cause taste issues. The easiest way to avoid these is to make sure that all your drinking water fittings are approved. Approved products should be clearly labeled. Though it’s not recommended to install an unapproved product in your drinking water pipe, selling them is not illegal, and many unapproved plumbing products are sold. All approved products must be clearly branded and tagged.