Tap water guides
18 guides on PFAS, lead, filters, testing and reading the reports your utility publishes. Each one starts with the short answer, cites its sources (EPA, CDC, NSF, state health agencies and manufacturer data sheets) and links the numbers to your own utility's page. Quick answers are in the FAQ.
PFAS
PFAS
What is UCMR 5? EPA's PFAS and lithium testing, explainedUCMR 5 is EPA's national screening of 29 PFAS and lithium in tap water. Learn who was tested, what the results mean and why a result is not a violation.PFAS
PFAS in tap water explained: what EPA's limits meanWhat PFAS are, which compounds EPA regulates, what 4 ppt means, the compliance timeline and what you can do if your utility reports detections.PFAS
PFAS in tap water by state: share of utilities above 4 pptA state-by-state table, computed from EPA UCMR 5 data, of the share of utilities serving 3,300+ people with PFOA or PFOS above EPA's 4 ppt level.
Lead
Lead
Lead in tap water: where it comes from and what to doHow lead gets into drinking water, why a utility's number is not your tap's, and EPA's steps: test, flush, use cold water and use a certified filter.Lead
Water filters certified to reduce leadHow to choose a filter for lead using EPA's guidance: NSF/ANSI 53 certification, Class I particulate reduction, replacement schedules and cold water only.Lead
Does boiling water remove lead, PFAS or other chemicals?Boiling kills germs but does not remove lead, PFAS, nitrate or other chemicals. What EPA, CDC and state health agencies say, and what to do instead.
Filters
Filters
Best water filter for PFAS at the tap: what to look forWhich filter types reduce PFAS, which certifications to check, and why a certificate is not proof of 4 ppt. Sources: EPA, CDC, NSF, Minnesota Health.Filters
Whole-house filter vs under-sink RO for PFASWhy a whole-house system is usually the wrong tool for PFAS, and when a point-of-use filter or reverse osmosis at the kitchen tap makes more sense.Filters
Reverse osmosis at home: pros, cons and what it removesWhat an under-sink RO system does well, the water it wastes, what it misses and the NSF/ANSI 58 certification to check. Based on EPA and WaterSense.Filters
NSF/ANSI 42, 53, 58, 401 and P473 explainedWhat the certification on a water filter means: aesthetic (42), health effects (53), reverse osmosis (58), emerging compounds (401) and PFAS protocol P473.Filters
Water softener vs water filter: what each doesA softener removes hardness minerals; a filter removes specific contaminants. Which standards apply and why softeners do not remove PFAS.Filters
Brita filters: what they are certified to removeBrita Standard vs Elite: which carries NSF/ANSI 53 lead claims, what chlorine certification means, and why U.S. data sheets list no PFAS claim.Filters
How often to change a water filterWhy replacement schedules matter for lead and PFAS claims, what EPA and WaterSense say about maintenance, and how to find your filter's interval.
Testing
Testing
How to test your tap water for leadWhy only a lab test shows lead at your tap, where to find a state-certified lab, how first-draw sampling works and how to read a result.Testing
Home water test kits compared: strips, mail-in and labsWhich test fits lead, PFAS, nitrate or well water: utility data, home strips, mail-in lab kits or a state-certified lab, and what each can and cannot show.
Reading your reports
Reading your reports
How to read your water quality report (CCR)What a Consumer Confidence Report contains, how to read MCL, MCLG and ppb, and what it leaves out, such as lead in your own plumbing.Reading your reports
How to find your water utility and its public dataFive ways to identify who supplies your tap water, what a PWS ID is, and where to find your utility's report, violations, lead and PFAS results.Reading your reports
What an MCL violation means for your drinking waterMCL, MCLG, action level, treatment technique and monitoring violations explained, plus the three tiers of public notice and what to do.
Not medical or legal advice. Guides summarize public documents. Where a guide names products, it does so only when a certifier's listing or the manufacturer's data sheet supports the claim, and the links are affiliate links: see the disclosure.