Rainwater might not be safe for household use without additional treatment.
Before using collected rainwater for drinking, bathing, or cooking, consider whether treatment is needed to make it safe. Testing the water can determine if there are harmful germs, chemicals, or toxins in it. Water treatment options include filtration, chemical disinfection, or boiling. Filtration can remove some germs and chemicals. Treating water with chlorine or iodine kills some germs but does not remove chemicals or toxins. Boiling the water will kill germs but will not remove chemicals. Using a simple device called a “first flush diverter” to remove the first water that comes into the system may help avoid some of these contaminants. The amount of water that should be removed by a first flush diverter depends on the size of the roof feeding into the collection system.
Consider adding a screen to the water inlet or emptying the rain barrel at least every 10 days to prevent mosquitoes from using the rain barrel as a breeding site.
Some people add purchased, treated water to the rainwater they collect in their cistern. This may make the treated water less safe.
Regularly test your collected rainwater and maintain your rainwater system.
If you collect and store rainwater for drinking, you have an individual water system and are responsible for ensuring that your water is safe. You should have your water and your system tested regularly and maintain the systemproperly. When rainwater is used as a supplemental water source, homeowners should ensure that rainwater cannot enter pipes containing safe drinking water. Contact your state or local health department for more information.
Check local regulations and guidance.
Your local health authorities might provide additional guidance on safely collecting rainwater. Rainwater collection is not allowed in all places. Some states consider rainwater the property of the state and regulate its collection, so you should consult with your local government (for example, your environmental quality department or health department) before proceeding.
