The Wirecutter Show — Episode Summary

Episode Title: How to Know What's In Your Drinking Water
Date: October 15, 2025
Hosts: Christine Cyr Clisset, Kyra Blackwell, Rosie Guerin
Guest: Tim Heffernan, Senior Staff Writer, Wirecutter (Home Improvement team)

Overview

This episode centers on a pressing, everyday concern: How can you know what's in your drinking water at home, and do you really need a water filter? The hosts, joined by Tim Heffernan—a veteran product tester and writer for Wirecutter—dive into the whys and hows of water testing and filtration. The discussion peels back the headlines about contaminants like microplastics, PFAS ("forever chemicals"), and lead, offering practical steps and product recommendations for those seeking cleaner, safer drinking water.

Key Discussion Points & Insights

1. The Motivation for Water Filtration

• Growing Concerns: News about contaminants (e.g., Flint, Newark's lead crises, microplastics, PFAS) has led to questions about safety, regardless of location.
  • “We continue to see news reports about microplastics, PFAS, … Flint, Michigan, … Newark, New Jersey… these are things that come up and they're big news stories. But I think people have questions about whether or not to filter their water, regardless of where they live.” — Rosie Guerin [01:43]
• Perceived Control: Filtering water can seem like a manageable, proactive step for health, though sometimes it might offer a false sense of security.
  • "Filtering my water… I feel like… at least I’ve got a little bit more security, whether it’s a false sense of security or not.”— Christine Cyr Clisset [02:17]

2. How Tim Heffernan Tests Water Filters and Kits

• Testing Process:
  • Water filters are tested in Tim’s home for usability, maintenance, and ergonomics—not just lab specs. Rigorous daily use simulates years of consumer use.
  • Contaminant reduction is checked via NSF/ANSI certification rather than proprietary lab setups.
    • “They will run between 120% and 200% of highly polluted water through the filter …and then measure if it meets the … pollution reduction standard." — Tim Heffernan [06:07]
• Water Test Kits:
  • More reliable kits require sending samples to certified labs (around $300 comprehensive report), as opposed to readily available but less accurate dip-strip paper kits.
    • “The dip strips, especially the ones that test for more contaminants, are extremely hard to read… the lab kits, … are telling you exactly what they found.” — Tim Heffernan [08:14]

3. Understanding Water Quality: Utilities & Regulation

• Regulations: Public supplies are EPA-regulated; local utilities must provide annual "Consumer Confidence Reports" (CCRs) about water quality.
  • “That utility has to release at least annually what’s called a consumer confidence report… Most of them do a really good job, not just of showing what they’ve found in the water, but what it means.” — Tim Heffernan [13:46]
• Why Filter?
  • Two main categories:
    • Aesthetic: Taste/odor (usually chlorine).
    • Health: Contaminants like lead, microplastics, PFAS, pesticides.
  • “It sort of breaks into two camps… Aesthetic concerns… basically taste. … Then the other half are... more serious contaminants that do have health impacts.” — Tim Heffernan [09:21]

4. Risks, Testing, and Personal Choices

• Risk Tolerance:
  • Choices depend on comfort level with potential, often minimal, risks.
  • Tim, after repeated testing, chooses not to filter due to consistently clean results; Christine still filters, preferring extra precaution.
  • “A filter is not going to do anything bad to your water, so you’re not adding to your risk by using one.” — Tim Heffernan [12:15]
• The Process to Decide:
  1. Check your annual CCR before considering testing/filtering.
     • “The first place I’d start… [is] your utility’s consumer confidence report.” — Tim Heffernan [13:46]
  2. If extra certainty is needed, invest in a certified home water test ($300+).
  3. For private wells (about 15% of US homes), regular at-home testing is essential since these aren't regulated.
     • “Those are not regulated. So many people on well water do get it tested.“ — Tim Heffernan [15:32]

5. Economic and Equity Issues

• Access & Affordability:
  • Comprehensive testing isn’t cheap. For those in low-resource communities, a certified pitcher filter (e.g., Brita) may offer reasonable protection for limited cost.
    • “…A basic pitcher filter that does get lead… is probably the most economical choice. Again, it's not going to harm your water in any way. And if there are contaminants… it will reduce or eliminate them in the water.” — Tim Heffernan [16:40]

6. Living Near Pollution Sources

• Proximity ≠ Contamination:
  • Water source and treatment matter more than closeness to potential industrial polluters (airports, factories, etc.).
    • “Proximity to pollution doesn't necessarily mean that your water will be polluted.” — Christine Cyr Clisset [33:16]
  • Airports especially can be sources of PFAS due to firefighting foam.
    • “Airports … are a known source of forever chemicals because of the firefighting foam.” — Tim Heffernan [19:04]

7. Types of Water Filters: Pros & Cons

a) Pitcher Filters

• Pros: Least expensive, simple to use & maintain, widely available.
• Cons: Clog easily, limited capacity (9-12 cups = ~10lbs), less effective for some contaminants.
  • “Gravity is not a very strong force. … Sediment in the water can clog the filters.” — Tim Heffernan [23:33]
• Best For: Those seeking basic filtration, cost-conscious, renters.

b) Faucet-mounted & Under-sink Filters

• Pros: Use water pressure for better contaminant removal, higher capacity, longer filter life.
  • “They use the water pressure in your pipes to force the water through… That means that the filter … can be made more dense, which … allows them to remove a wider range of contaminants.” — Tim Heffernan [25:01]
• Cons: Installation required, can’t use on all faucet types, costlier (but sometimes offsets regular filter changes), risk of damaging filter if hot water is used.
• Best For: Those with higher usage, want more thorough filtration, homeowners/long-term renters.
• Top Picks:
  • Under-sink: Aquasana AQ5200 and AQ5300+ ($100–$180)
  • Faucet mount: Pureplus Faucet Filter (~$50)
    • “Wait around for [Aquasana] to drop again, because it will.” — Tim Heffernan [27:49]

c) Countertop Gravity Filters (e.g., Big Berkey)

• Pros: Massive capacity (up to 6000 gallons before filter change), no plumbing needed.
• Cons: Huge size, risk of bacteria & algae buildup, not certified for NSF standards.
  • “They breed algae and bacteria to the point that this is a known issue. Also, they are not certified…” — Tim Heffernan [28:31]

d) Homeopathic/Alternative Methods (e.g., Floating Charcoal Sticks)

• “I think that they likely don’t do anything… unless the contaminants are actually coming in contact with [the charcoal], they’re not going to…” — Tim Heffernan [29:51]
• Leaving water out overnight can remove most chlorine due to off-gassing.

Product Recommendations

• Pitcher Filters: Basic Brita-type pitchers (affordable & accessible for most users)
• Under-sink Filters: Aquasana AQ5200, AQ5300+
• Faucet Mount Filters: Pureplus Faucet Filter
• Well Water Test Kits: SimpleLab Tap Score Well Water Test

Notable Quotes & Memorable Moments

• On Risk and Filtering:
  • “A filter is not going to do anything bad to your water, so you’re not adding to your risk by using one.” — Tim Heffernan [12:15]
• On Accessibility of Information:
  • “You can sometimes, just for free, really know basically what’s in your water… It’s really just the not knowing, combined with these, frankly, really alarming headlines that keep popping up…” — Tim Heffernan [30:56]
• On Headlines and Anxiety:
  • “It’s possible your water will contain these things. It’s also very, very possible it doesn’t contain them.” — Tim Heffernan [09:21]
• Listener Takeaways:
  • “I am not going to do anything. I’m going to keep drinking straight from the tap.” — Kyra Blackwell [32:33]
  • “I think I might get a Brita again. … It’s a fairly low barrier to entry for folks.” — Rosie Guerin [32:53]
  • “I am still very much team filter my water even though I know that the water in New York City is safe to drink.” — Christine Cyr Clisset [33:16]
• On Proximity to Pollution:
  • “Proximity to pollution doesn't necessarily mean that your water will be polluted… it comes down to your water source and how the water is treated.” — Christine Cyr Clisset [33:16]

Actionable Steps for Listeners

1. Check your utility’s Consumer Confidence Report (CCR) before considering further action. Look online (search for "EPA CCR") or via your water bill provider.
2. If you need absolute certainty (e.g., older home with lead risks, unexplained taste), invest in a lab-based home test (~$300+).
3. For well water users: Test regularly, look for local agricultural extension support or use certified kits.
4. For many, a basic certified pitcher filter suffices—especially where cost is a concern, or if you just want to remove taste/odor issues.
5. Remember: Proximity to industrial sites doesn’t always equal water contamination; source and treatment are key.

Episode Highlights by Timestamp

• Introduction and concern over water quality: [01:19–02:58]
• Tim describes testing water filters & kits: [05:47–08:54]
• Why people filter water (taste vs. health risks): [09:21–10:18]
• Tim’s own water choice—why he stopped filtering: [10:54–11:57]
• How to start: CCR, home testing, costs: [13:36–14:40]
• What to do for private wells: [15:12–16:18]
• Equity/access issues in water testing/filtration: [16:18–17:15]
• Living near pollution, real vs. perceived risks: [18:26–20:18]
• Pros and cons of pitcher, faucet, and under-sink filters: [22:45–27:49]
• About the Big Berkey: [28:23–29:31]
• Homeopathic/alternative “filters” (charcoal sticks): [29:41–30:47]
• Single most important takeaway: [30:48–31:37]
• Co-hosts’ personal takeaways and sign-off: [32:28–33:51]

Final Takeaway

“You can sometimes, just for free, really know basically what’s in your water. …Knowing what’s in it will help you choose the right filter and the right amount of filtration that you need.” — Tim Heffernan [30:56]

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For more Wirecutter recommendations and detailed buying guides, visit their website or see episode show notes.