# Is PEX safe for drinking water?

> Is PEX safe for drinking water? What NSF/ANSI 61 certification tests, taste and odor in new pipe, chloramine ratings, microplastics and PEX-A vs PEX-B.

URL: https://gracklerepipingaustin.com/guide/is-pex-safe-for-drinking-water/

Yes. PEX tubing sold for drinking water is tested against NSF/ANSI 61, the national standard for the health effects of products that touch drinking water, and certified tubing carries that mark on its printed line. Certification limits what the pipe may add to the water. It does not make PEX immune to failure, and it does not settle every open question. [Grackle Repiping Austin](https://gracklerepipingaustin.com/) offers and manages PEX repipes across the Austin area, and this guide explains what “safe” covers.

Key takeaways

- Look for NSF/ANSI 61 (often shown with NSF-pw) in the print line on the tubing
- New PEX can give water a faint taste or odor at first; flushing reduces it
- PEX carries a chlorine-resistance rating because disinfected hot water slowly attacks it
- Austin Water disinfects with chloramine; Kyle reports free chlorine
- There is no settled answer yet on microplastics from household pipe of any material

## What NSF/ANSI 61 certification means

NSF/ANSI 61 is a standard for drinking water system components: pipe, fittings, valves, tanks and the like. A product certified to it has been exposed to test water, and the water has been analyzed for what extracted from the product. Each contaminant found must stay under a limit set on health grounds. Certifiers also audit the factory, so the certification covers ongoing production, not one sample.

The same standard shows up elsewhere in Austin’s code. Austin’s amendment 608.2 requires an NSF 61 expansion tank downstream of a pressure regulator, which is the same family of test applied to a different part.

What certification does **not** cover is just as useful to know:

- It does not rate durability. A certified pipe can still leak at a bad fitting or crack in a freeze.
- It does not cover installation. Uncertified fittings, unlisted transitions or tubing left in sunlight are installation problems, not material ones.
- It does not measure microplastic particles. The test looks at chemical compounds extracted into water.

## How to read the print line on PEX tubing

PEX tubing is printed every few feet with its details. On tubing meant for drinking water, expect to find:

- the material and type, such as PEX-A or PEX-B
- the tubing standard it is made to
- pressure and temperature ratings for cold and hot water
- a chlorine-resistance designation
- a potable water certification mark, often written as NSF-pw, sometimes alongside NSF 61

If you can see tubing at the water heater, under a sink or in the attic, read the print line. Unprinted or unreadable tubing is a question to raise during an assessment, not proof of a problem. The [pipe identification guide](https://gracklerepipingaustin.com/guide/what-kind-of-pipes-do-i-have/) shows where pipe is visible in a typical house and how PEX differs from polybutylene, which can look similar.

## Taste, odor and what leaches from new pipe

New plastic pipe can release small amounts of compounds from manufacturing in its first weeks of use, which some people notice as a faint plastic taste or odor, especially from water that sat overnight in the hot lines. Certification is what keeps those compounds under health-based limits; flushing is what clears most of them. A repipe ends with a flush of every fixture after the pressure test, and running cold water for a minute after it has sat for a long stretch helps in the first weeks.

A taste or odor that persists, that starts suddenly in an older system, or that comes only from the hot side points elsewhere. Water heaters commonly cause hot-side odor. The [low water pressure guide](https://gracklerepipingaustin.com/guide/low-water-pressure-austin/) and the [Austin hard water guide](https://gracklerepipingaustin.com/guide/austin-hard-water-and-pipes/) cover other changes people notice at the tap.

## Chlorine, chloramine and PEX

Utilities add disinfectant so water stays safe all the way to the tap. That same disinfectant, especially in hot water, slowly oxidizes PEX from the inside over its life. The tubing standards therefore test PEX against chlorinated hot water and assign a chlorine-resistance rating, printed on the tubing. Higher ratings are meant for harder service, such as a hot-water recirculation loop that keeps hot disinfected water moving through the pipe all day.

The disinfectant depends on who supplies the house:

| Utility | Disinfectant reported | Level reported |
| --- | --- | --- |
| Austin Water | Chloramine | 0.06 to 3.1 ppm, average 2.3 ppm |
| Round Rock | Chloramine | average 2.41 ppm |
| Cedar Park | Chloramine | average 3.09 ppm |
| Leander | Chloramines | 2.40 mg/L |
| Kyle | Free chlorine | averages of 1.43 and 1.81 mg/L at two systems |
| Georgetown | Total chlorine | see the City of Georgetown water quality report |

These are each utility’s own reported figures. What matters for the pipe is matching the tubing’s rating to the service it will see, keeping hot water within the tubing’s temperature rating, and thinking twice about a recirculation pump that runs around the clock. The [PEX vs copper guide](https://gracklerepipingaustin.com/guide/pex-vs-copper/) explains how the same water affects copper.

## Microplastics and plastic pipe

People increasingly ask whether PEX sheds microplastics into drinking water. The honest answer is that there is no settled measure for how much, if anything, household plastic pipe contributes, and no drinking water standard for microplastic particles to test it against. NSF/ANSI 61 addresses chemical compounds extracted into water, not particles. Copper and galvanized pipe raise their own questions about metals. If microplastics are your deciding concern, that is a reasonable preference to state, and copper is the alternative; the [copper repiping page](https://gracklerepipingaustin.com/copper-repiping/) covers what it involves.

## Where PEX can fail

Safe to drink from is a different question from durable, and PEX can fail. The ways it does are well understood:

- **Sunlight.** Ultraviolet light breaks PEX down. Tubing must be covered or shielded where light reaches it, including near attic gable vents.
- **Fittings.** Crimp rings set wrong, fittings not rated for the tubing, or brass fittings that corrode in some waters can leak while the tubing is fine.
- **Heat and support.** Tubing run on a hot roof deck or left to sag wears faster. The [PEX in a Texas attic guide](https://gracklerepipingaustin.com/guide/pex-in-attic-texas/) covers routing.
- **Freeze.** PEX tolerates ice better than copper but is not freeze-proof; fittings and fixtures can crack.
- **Contaminated soil.** Buried PEX can be permeated by petroleum products and solvents, so it is kept away from them in yard lines.

Homeowners in Austin-area forums report early leaks in PEX systems in houses only ten or so years old, and one reports a house repiped through the attic after repeated leaks from its original under-slab PEX. Those are individual accounts, not a measured failure rate, and no product line is singled out here. They are a reason to check the print line, the fittings and the installation, not a reason to fear PEX as a material.

## Choosing PEX with confidence

If PEX is the plan for your house, three checks cover the ground this guide describes. The tubing carries a potable water certification mark and a chlorine rating suited to the service. Fittings and transitions are listed for that tubing. Routing keeps it out of sunlight, supported and on the warm side of attic insulation, with the R-4 insulation Austin’s code requires on lines outside the thermal envelope. A [PEX repipe](https://gracklerepipingaustin.com/pex-repiping/) in Austin is then pressure tested and inspected by the City before walls close, and flushed before you use it. The [repipe cost guide](https://gracklerepipingaustin.com/guide/repipe-cost-austin/) explains what that work typically costs, and the [whole-house repiping page](https://gracklerepipingaustin.com/whole-house-repiping/) explains the full scope.

## Questions about this guide

### Why does water from new PEX taste or smell different?

New plastic pipe can release small amounts of compounds left from manufacturing, which some people notice as a faint plastic taste or odor at first. Flushing the system after installation reduces it, and it usually fades as the pipe is used. A taste that persists, or appears suddenly in old pipe, should be checked.

### Is PEX-B as safe as PEX-A for drinking water?

The letter describes how the polyethylene is cross-linked, not whether it is safe to drink from. PEX-A and PEX-B tubing sold for potable water are certified to the same drinking water health standard. What to check is the certification mark printed on the tubing you are actually getting.

### Does Austin's chloramine damage PEX?

Chlorinated and chloraminated hot water slowly oxidizes PEX over its life, which is why PEX carries a chlorine-resistance rating. Austin Water disinfects with chloramine at an average of 2.3 ppm. Tubing with a suitable rating, installed within its temperature limits, is designed for that service; a recirculating hot loop is the demanding case.

## Related service

### PEX repiping

A whole-house or partial repipe in PEX tubing, with the tubing type, fittings and layout chosen for the house and run to Austin's attic and pressure rules.

Details →

## More guides

- Decision Guide [PEX vs copper: which pipe should an Austin house be repiped with?](https://gracklerepipingaustin.com/guide/pex-vs-copper/)Neither pipe wins everywhere. This guide compares PEX and copper on the things that decide an Austin repipe: price and access, attic heat and freeze, the water your utility delivers, joints and the layout of the house.
- Learn [Can PEX run through an attic in Texas?](https://gracklerepipingaustin.com/guide/pex-in-attic-texas/)Why slab-home water lines end up in the attic, what Austin's code requires for them, and how routing, insulation, support and sun protection decide whether attic PEX does well through a Texas summer and a hard freeze.
- Learn [Does Austin have hard water, and what does it do to pipes?](https://gracklerepipingaustin.com/guide/austin-hard-water-and-pipes/)Austin Water delivers moderately hard, lime-softened water, while several suburbs deliver much harder water. This guide compares the utilities' own figures and explains what hardness, pH and disinfectant do to pipe, fixtures and water heaters.
- Learn [What kind of pipes does my house have?](https://gracklerepipingaustin.com/guide/what-kind-of-pipes-do-i-have/)You can identify most water pipe yourself in a few minutes by looking where it shows: the water heater, the main shutoff, under sinks and in the attic or crawlspace. This guide shows what each material looks like, what its age suggests and what each one tends to need.
- Decision Guide [Is repiping worth it, or should I keep fixing leaks?](https://gracklerepipingaustin.com/guide/is-repiping-worth-it/)Repiping is worth it when the pipe itself is the problem: leaks keep coming in different places, the material is known for failing, or the house is being bought or sold with it. When one line has failed in otherwise sound pipe, a repair or reroute is the better buy.