During and after our recent show about tap water contamination beyond Flint, Michigan, many of our listeners had questions about how to ensure their families’ safety. Our panelist Erik Olson, who is the director of the National Resources Defense Council’s health program, and the team at DC Water answer a selection of them below.

1. Who should get their water tested for safety? And what’s the best way to go about getting that done?

Erik Olson: If you are pregnant or have young children using water in your home for drinking or cooking, it would be worth testing your water for lead. Even some newer homes can have lead in the faucets and fixtures, and older homes may have lead service lines and lead in the pipes and fittings. Also, if you are immunocompromised, some experts recommend that you consider using ozone-disinfected bottled water (check the label or call the bottler) or boil your water before drinking it.

Some drinking water utilities will test your water for free or at a discount. A low-cost test for lead in your water is being offered by the non-profit organization Healthy Babies Bright Futures. You also can go to a state-certified laboratory in your state; check EPA’s website for a list. Additionally, some national labs (such as Watercheck) that are certified in many states can test for lead and other contaminants.

DC Water: We believe that anyone concerned about their tap water should get it tested, and especially in those homes where children 6 and under and pregnant women reside.

Start with contacting your local water utility or looking at their website for information about the water quality. Water utilities are required to test for thousands of contaminants and report the detects in an annual report. Contaminants found in drinking water sources vary geographically and often by treatment plants.

For those who can’t find the information with their local water authority, EPA Region 3 suggests calling the EPA’s Safe Drinking Water Hotline at 1-800-426-4791. If their water utility is unable to analyze the customer’s water sample, they should use a state-certified laboratory. Their water utility can help them identify a laboratory and each state maintains information on certified laboratories.

2. “What do you do if you find out that your system is contaminated?” (tweet from Morgan)

EO: Go with a filter that is NSF-certified to remove the contaminant in your water (see guidance for selecting a filter here)—just be sure to regularly change the filter and maintain it as recommended, or it could make things worse. Bottled water is also an option when you know you have a tap water problem, though it isn’t necessarily cleaner than typical city tap water; in the case of known tap water contamination, it is worth considering.

DCW: If your water has lead, or you have a lead source, then you should immediately begin using filters for your tap water with a filter certified for lead removal while working to remove all lead sources.

3. What’s the best material for pipes? (tweet from John) Is CPVC safe? (tweet from Reasonable Tom)

EO: Copper pipes work well, assuming that your water isn’t too corrosive. Some plastic pipes can withstand corrosive water, but in some cases can leach low levels of plasticizing chemicals into the water.

DCW: Pipe materials must be approved for potable water use. Each type of material has advantages and disadvantages. Copper is a microbial inhibitor but can corrode under certain water conditions. CPVC and plastic pipes are much less expensive than copper but allow for microbial growth.

4. Are store-bought filters (BRITA, etc.) effective for making water safe to drink? (tweets from Amir and Holly) How effective are home water filters, such as those that attach directly to faucets or those built into refrigerators? (email from Nathan)

EO: See advice here on selecting a water filter. The bottom line is you need to get a filter that is certified by NSF to remove the contaminants you’re worried about. It is very important to maintain it as recommended by the manufacturer, or it can make things worse. If you’re not great at remembering to maintain it, consider a maintenance contract with the filter dealer.

DCW: The filters are tested by a third party to ensure they achieve the 99% removal of the contaminant the package lists it is certified to remove (if the package does not say it is certified for lead removal, then it likely has not been designed for lead removal). Replacing the filter cartridges is very important and should be done at least at the frequency recommended by the manufacturer.

5. “End-user testing is great for people who can afford it, but for those in economically depressed areas, the highest risk areas, what are the options available?” (Facebook message from Melanie)

EO: Some drinking water utilities will test your water for free or at a discount—call and ask them. If you’re worried about lead, a low-cost option for testing is the new Healthy Babies Bright Futures testing program. The bottom line is that your drinking water system is legally responsible for providing safe drinking water to its customers. It shouldn’t be up to you to ensure that it’s safe.

DCW: Everyone should filter their tap water if they have a lead source (lead service line, lead solder). Testing the water helps to identify if you have a lead pipe. People can look at the pipe coming into the home and if visible see if it is lead. Lead pipe is gray and can be scratched with a nail or key. A plumber can also help identify lead fixtures and plumbing.

6. How can private well owners protect themselves? “Certainly the run off of nitrates, pesticides and other possible contaminants are not filtered our by the basic sterilization (UV lights) or other filtering methods (sand systems for debris removal, etc.)” (Facebook post from Judith)

EO: Private wells are not protected under the Safe Drinking Water Act; owners should periodically test their water at least for bacteria and nitrates, and if you live in an agricultural area consider testing for pesticides. For water testing go to a state-certified laboratory in your state; check the EPA’s website for a list. Additionally, some national labs (such as Watercheck) that are certified in many states also can test for lead and other contaminants. Disinfection is a good idea, using a certified filter or UV treatment device. For guidance on filter selection see here.

7. “We purchased a reverse osmosis system when the local water had traces of arsenic. It cost $400-500. Would it be cheaper to give every affect home in Flint such a system?” (email from Steve from OK)

Erik Olson: Purchasing and regularly maintaining sophisticated reverse osmosis or comparable filtration systems can be very expensive over time, and if they are not properly maintained on a regular basis can break down or even make things worse. The maintenance costs can be substantial. NRDC believes that every consumer of water from a public water system has a right to safe drinking water, and should not have to further treat their tap water. If there is a serious infrastructure problem in a distressed community such as Flint, state and federal resources should help pay to upgrade the system.

8. “What was the name of the app mentioned that allows you to find free water for reusable bottles?” (tweet from Stephanie)

EO: I will leave this to DC Water, but the national app is here.

DCW: TapIt Metro DC is the app to locate businesses that allow free refills into reusable water bottles. Free smartphone applications make it easy to find the nearest TapIt Metro D.C. location, and a map of participating businesses can be viewed at the app’s website.

9. “My question is in regards to cities downstream from Flint. Is the dissolved lead now a problem in the water, as opposed to being in the lead pipe. The added phosphate protects from the lead in the pipe, but what removes the dissolved lead from the source?” (email from Ed)

EO: Generally, lead in drinking water comes from the pipes that carry the water from the water main to your residence (the “lead service line”) or it can come from lead-containing pipes, solder, or fixtures (such as kitchen faucets) in your home. Significant amounts of lead were allowed in fixtures until recently. The only thing that will remove dissolved lead from your tap water is either flushing your pipes for several minutes so that the water is coming directly from the water main (please use that water to water plants, wash clothes, shower, etc.; this often is not feasible in a multi-family dwelling), or to use a filter that is NSF-certified for lead removal (see filter selection advice here).