Many countries, including the US, have guidelines to ensure that harmful chemicals in your water and overall water quality are tested and regulated.
In the US, the EPA has legally applicable standards for all the different types of contaminants in your drinking water as well secondary concerns which can cause skin irritation or affect your hair. Your local water supplier should produce a new Consumer Confidence Report every year, a EPA has a public database designed to allow you to easily search for the latest tap water report for your area. You can read the report and see if there are worrisome levels of contaminants in your water, but you can also be safe in the knowledge that if a water contaminant is above its legal limit, your community will certainly be notified.
If you're particularly concerned about lead, one easy way to reduce that risk is to simply run your tap water a few minutes before you use it. The most dangerous amounts of lead build up when water sits in your home's pipes overnight, so getting that water out of the lines will put you in better shape.
Lead and chlorine in drinking water
Even if your water smells and tastes good, that doesn't mean your tap water is free of harmful chemicals. Water contaminants fall into various categories, but the most important ones in shower water are toxic metals, chlorine (which is used as a disinfectant), and the byproducts that chlorine creates with all the other chemicals in the water. Any of these can put a big squeeze on your showering experience.
The main toxic metals often found in water are arsenic, lead, cadmium and mercury, all of which have World Health Organization Top 10 List of “chemicals of major health concern”.
Lead from degrading plumbing can enter drinking water, causing public health problems.
Lead is often considered the biggest pollutant, even if your water supply is clean, the water slowly corrodes the lead in the home's plumbing systems, and the toxic metal seeps into the water. Children are at particularly high risk from harsh chemicals and have been reported to absorb up to 50% of their lead through drinking water. Even at relatively low levels, lead exposure can cause irreversible neurological problems, according to the WHO. This is why water quality must always be considered.
Another major problem is related to the chlorine used as a disinfectant in our drinking water. The main health concern is actually the byproducts that are created when chlorine reacts with the natural organic matter in the water, creating harmful chemicals called THMs. You've probably heard of chloroform, which is just one common THM, and high levels of THMs are carcinogenic.
A study found that people absorb more THM from a 10-minute hot shower than from drinking a liter of water, so if you're concerned about this, a shower filtration system that actively removes chlorine can be helpful.