Do I Need a Permit to Convert a Bathtub to a Walk-In Shower? in Polen
Converting a bathtub to a walk-in (curbless or low-threshold) shower is one of the most popular aging-in-place and bathroom modernization projects. In most jurisdictions, it requires a plumbing permit because the conversion involves relocating or resizing the drain from a bathtub drain (typically 1.5-inch with an overflow) to a shower drain (2-inch minimum per code, often with a linear drain body), modifying the water supply rough-in for a new valve position, and changing the waterproofing membrane (the shower pan liner or sheet membrane system must meet code requirements that differ from a bathtub surround). An electrical permit is also required if the project adds or relocates a GFCI-protected outlet, exhaust fan, or recessed lighting in the wet area. The conversion frequently involves structural work — cutting into the subfloor to reposition the drain, adding blocking for grab bars, or modifying the curb — which triggers a building permit in addition to the plumbing permit.
Do you need a permit?
Sometimes
- Permitting authority
- Powiatowy Inspektorat Nadzoru Budowlanego (PINB)
- Typical fee
- 0–300 zł
What triggers a permit
- Relocating or resizing the drain from a 1.5-inch bathtub drain to a 2-inch shower drain
- Modifying the water supply rough-in (moving valve body, adding a thermostatic mixing valve or diverter)
- Cutting into the subfloor or floor joists to reroute the drain line to a new position
- Installing a new shower waterproofing system (pan liner, sheet membrane, or liquid-applied membrane)
Country-specific detail
In Poland, converting a wanna (bathtub) to a kabina prysznicowa (walk-in shower) within an existing łazienka is typically classified as a remont (renovation) under Prawo budowlane, which does not require a pozwolenie na budowę or zgłoszenie as long as the work does not alter the strop (floor structure), ściany nośne (load-bearing walls), or the location of the pion kanalizacyjny (main drain stack). A simple swap where the new shower drain connects to the same pion at the same point usually qualifies as a remont. However, if the conversion requires cutting into the strop to reposition the drain, adding a pompa zatapialna (waste pump) for a below-grade installation, or moving the pion, it becomes a przebudowa (reconstruction) requiring at minimum a zgłoszenie. In budynki wielorodzinne (apartment buildings), the wspólnota mieszkaniowa (housing community) may require notification or approval for work affecting wspólne instalacje (common systems). The instalacja wod-kan must comply with PN-EN 12056 for drainage sizing.