Your Pipes Are Plastic (And They're Dissolving Into Your Water)

A licensed plumber recently left a comment on our Reddit post that stopped me in my tracks:

"I'm a plumber in Riverside, but work in LA/OC/SD. My area is having an epidemic of pinhole leaks on houses with PEX piping. The oxidants in the water cause extreme degradation (chlorine, chloramine, ozone) and the pipes are failing. Think: if the pipe is degrading and leaking, it's literally releasing parts of itself into the water inside the home. This is accelerated 10 fold on hot water and even more if there's a recirculating pump."

This comment had me rethinking everything we've seen in our data.

Wait — My Pipes Are Plastic?

This is the part that surprises most people. If your LA home was re-piped anytime in the last 20 years, there's a 99% chance it was done with PEX — Poly Ethylene Crosslink. It's the industry standard. Plumbers use it because it's flexible, affordable, and easy to install compared to copper.

PEX is plastic.

Most homeowners have no idea. They see the plumber show up, rip out the old pipes, put in new ones, and assume everything is good. Nobody says "hey, we're running all your water through plastic tubes now."

And it's not just re-piped homes. Older houses may have PVC or CPVC supply lines — also plastic. Unless your home has copper throughout (increasingly rare in modern plumbing), your water is sitting in plastic pipes before it reaches your glass.

The Mechanism: How Your Pipes Shed Plastic

Here's what's actually happening inside your walls.

Municipal water suppliers add chlorine and chloramine to your water. These are oxidants — they kill bacteria and keep the water safe from biological contamination. That's their job, and they're good at it.

But these same oxidants also attack plastic piping. Over time, they cause chemical degradation of the PEX polymer. The pipe breaks down at a molecular level. And when it breaks down, it releases microscopic particles of itself directly into the water flowing through it.

This isn't theoretical. Plumbers across the LA basin are seeing an epidemic of pinhole leaks in PEX piping — visible evidence that the material is failing. If a pipe is degrading enough to develop holes, it's been shedding particles into the water for years before that hole appeared.

Hot Water Makes It 10x Worse

This was the detail that hit hardest. According to the plumber's experience:

• Hot water accelerates PEX degradation by up to 10x compared to cold water
• If your home has a hot water recirculating pump (common in larger LA homes), the effect is even worse — water is constantly cycling through plastic pipes 24/7

Think about what that means. Every time you make coffee with hot tap water, run a hot shower, or fill a pot from the hot side — you're getting water that's been sitting in a plastic pipe at elevated temperatures, accelerating the breakdown of that pipe.

Most people never think to test their hot water separately from their cold. We're starting to recommend it.

What Our Data Shows

We've now tested 50+ homes across LA, and the pattern the plumber described matches what we see in our data:

The municipal supply is relatively consistent within a distribution zone. Two homes on the same block, pulling from the same water main, should be getting essentially the same water from the city.

But the results at the tap are often completely different. One apartment shows 3 particles, the neighbor shows 15+. Same block. Same water main. Different plumbing.

This is exactly what you'd expect if internal plumbing — specifically the type, age, and condition of the pipes — is the primary variable driving microplastic levels at the tap.

Building age matters too. Older buildings with original plumbing may have different degradation patterns than recently re-piped homes. But the common thread is plastic pipe + oxidant-rich municipal water = particle shedding.

What You Can Do About It

The plumber who left the Reddit comment has been running a specific filtration setup on his own home for 3 years and tests his water 3-4 times per year to verify it works. Here's the approach:

1. Whole-House Catalytic Carbon Filter with KDF Media

Install this at the point of entry to your home (where the main water line comes in). This type of filter removes chlorine, chloramine, and other oxidants from the water before it reaches your pipes.

The logic is straightforward: if oxidants are what's degrading your pipes, removing the oxidants stops the degradation. Your pipes last longer, and they stop shedding particles.

KDF (Kinetic Degradation Fluxion) is a copper-zinc alloy media that also controls bacteria and mold — which can be an issue with some plastic piping systems.

2. Salt-Based Water Softener (Optional)

Some plumbing professionals add a salt-based softener to further reduce the water's ability to attack the piping. This may or may not be necessary depending on your water hardness and pipe condition.

3. Point-of-Use Reverse Osmosis Filter

For drinking water specifically, an RO filter at the kitchen tap is highly effective at catching particles that have already been released from the pipes. Our data consistently shows RO-filtered samples coming back with significantly lower particle counts than unfiltered tap from the same home.

4. Simple Behavioral Changes

• Run cold water for 30 seconds before drinking — this flushes standing water that's been sitting in contact with your pipes
• Don't drink from the hot tap — use cold water and heat it separately if needed
• Test your water to establish a baseline, then test again after installing filtration to verify it's working

Why This Matters for Testing

This whole thread reinforces why neighborhood-level testing is so valuable. If the variable is your home's plumbing — not the municipal supply — then the only way to know your exposure level is to test your specific tap.

Your neighbor's results don't tell you about your pipes. The city's water report doesn't tell you about your pipes. Only testing your water, from your tap, tells you what's actually in your glass.

Some ideas we're exploring:

• Hot water vs. cold water comparison kits — test both sides to see how much your hot water system is contributing
• Before/after filter verification — install a whole-house filter, then re-test to prove it's working
• Building age correlations — mapping our results against building age data to quantify the relationship between plumbing age and particle counts

The Bottom Line

Most people's mental model is: the city sends clean water, and it arrives clean at their tap. The reality is more nuanced. The city sends water treated with oxidants (which is good — it kills bacteria). Those oxidants then spend hours or days in contact with your plastic pipes (which is bad — it degrades them). And the degradation products end up in your glass.

The good news: this is a solvable problem. A whole-house carbon filter at the point of entry can dramatically reduce the oxidant load on your pipes. An RO filter at the tap catches what gets through. And testing gives you the data to know whether it's working.

If you want to find out what's in your water — and specifically whether your pipes are contributing — order a test kit. Two vials, $99 with free shipping, results in 48 hours.

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Thanks to u/Disastrous-Number-88 for the expert insight that inspired this post. If you're a plumber, water quality professional, or researcher and want to collaborate on this project, reach out via our support chat.