Do You Need a Permit for Whole-House Water Filtration? in Nederland
Installing a whole-house water filtration, softener, or reverse-osmosis system may require a plumbing permit because the work involves cutting into the main water supply line and adding fittings. Under-sink point-of-use filters typically do not need a permit. The key factor is whether the installation modifies the domestic plumbing beyond simply attaching to an existing connection. Systems with a drain connection (for backwash or RO reject water) are more likely to trigger permit requirements.
Do you need a permit?
Rarely required
- Permitting authority
- Gemeente / Waterbedrijf
- Typical fee
- €0
What triggers a permit
- Cutting into or teeing off the main domestic water supply line
- Adding a drain connection for filter backwash or RO reject water
- Installing a loop or bypass that requires soldering or PEX connections in the plumbing system
- Adding an electrical circuit for a UV sterilizer or RO booster pump
- Installing a system that requires a pressure-reducing valve or expansion tank modification
Country-specific detail
In the Netherlands, installing a waterontharder (water softener) or waterfilter connected to the existing leidingwater system is generally vergunningvrij. However, the Drinkwaterwet requires that any modification to the drinkwaterinstallatie maintains hygienic safety. The local waterbedrijf (e.g., Vitens, Evides, PWN) may require notification or inspection if the system is connected directly to their supply. Systems must comply with NEN 1006 (general requirements for drinking water installations). Discharge of backwash water to the riolering must meet local lozingsvoorwaarden.