# What filament is waterproof?

Watertightness is mostly walls, flow, and temperature, not a magic polymer. PETG is the usual community pick, ASA is the other rigid option, and a critical part still needs an epoxy coat.

## When to use which material

Start with [PETG](/material/petg). Use [ASA](/material/asa) when the part is also outdoors and you can print ASA. Do not pick a fiber-filled grade to stop a leak. The leak path is between layers. [PLA](/material/pla) is not the consensus pick for a vessel.

## Temperatures and settings

Print hot enough to fuse the walls, inside the nozzle range on the row. Prusament PETG lists 240–260 °C. PolyLite PETG lists 220–250 °C. Add walls and keep flow high enough that the seams close. Those two settings are not stored on the filament record. Dry PETG first. Wet PETG is a [drying](/answers/drying) problem and it will not seal.

## Failure modes

A leak at the seam is under-extrusion or too few walls, not a bad brand. A leak after a week outside may be the wrong polymer for sun, which is the [outdoor](/answers/outdoor) question. A part that must not leak even if a layer is short is the epoxy case. The coat is not optional for critical use in this consensus.

## Caveats

Nothing in the table is a waterproof certification. Epoxy is recommended for critical use and is absent from the filament catalog. Do not describe a PETG datasheet as a hydrostatic rating.

## Where this sits in the catalog

[Prusament PETG versus PolyLite PETG](/compare/prusament-petg-vs-polymaker-polylite-petg) is the pair of usual picks. [Bambu ASA versus Prusament ASA](/compare/bambu-lab-asa-vs-prusament-asa) is the ASA pair if the part also lives outside. Printer fit for PolyLite PETG on a P1S is [that settings page](/printer/bambu-lab-p1s/polymaker/polylite-petg).

Updated 2026-10-14. Sources accessed 2026-10-14. Use case: Watertight.

## Ranked filaments

| Rank | Filament | Nozzle | Bed | Price per kg |
| --- | --- | --- | --- | --- |
| 1 | Prusament PETG | 240–260 °C | 70–90 °C | — |
| 2 | Polymaker Polylite PETG | 220–250 °C | 70–90 °C | — |
| 3 | Bambu Lab ASA | 235–260 °C | 90–110 °C | — |

## What the community says

The consensus is that watertightness is mostly settings, meaning walls, flow, and temperature. PETG is the usual pick. ASA is also named. An epoxy coat is the recommendation for critical use.

## Sources

- [Prusament PETG technical data sheet](https://www.prusa3d.com/file/3464616/prusament-petg-technical-data-sheet.pdf) (datasheet)
- [PolyLite PETG technical data sheet](https://cdn.shopify.com/s/files/1/0548/7299/7945/files/PolyLite_PETG_TDS_EN_V5.4.pdf) (datasheet)
- [Bambu Lab ASA technical data sheet](https://cdn.shopify.com/s/files/1/0645/5876/0155/files/Bambu_ASA_Technical_Data_Sheet.pdf) (datasheet)
- [Community source, r/3Dprinting 1nff6t6](https://www.reddit.com/r/3Dprinting/comments/1nff6t6/) (reddit)
- [Community source, r/ender3 12273n7](https://www.reddit.com/r/ender3/comments/12273n7/) (reddit)
- [Community source, r/3Dprinting zx9yin](https://www.reddit.com/r/3Dprinting/comments/zx9yin/) (reddit)
- [Community source, r/FixMyPrint u150hn](https://www.reddit.com/r/FixMyPrint/comments/u150hn/) (reddit)
- [Community source, r/3Dprinting 105qbp8](https://www.reddit.com/r/3Dprinting/comments/105qbp8/) (reddit)

HTML: https://filamentfacts.com/answers/waterproof