Hard water by region
Hard water in Île-de-France
In Île-de-France, water hardness ranges from 25 to 40 °fH. This level drives how quickly limescale builds up in pipes, water heaters and appliances. Find the LIMPEO solution that fits your situation.
Local geology
bassin parisien calcaire
Departments covered
8 departments
Limescale risk level
Hard water — protection recommended
Departments of Île-de-France
Hardness can vary by several °fH depending on the department and municipality. Verify exact hardness on your water bill or via the interactive map below.
- 75
- 77
- 78
- 91
- 92
- 93
- 94
- 95
Main cities in Île-de-France
Key cities exposed to the regional average hardness.
- Paris
- Boulogne-Billancourt
- Saint-Denis
- Argenteuil
- Versailles
Our recommendation
The right LIMPEO protection for Île-de-France
Hard water in Île-de-France causes visible deposits within months (water heater, faucets, shower, dishwasher). LIMPEO protection is strongly recommended to preserve your equipment.
LIMPEO solution at a glance
- No salt, no chemicals, no maintenance
- Non-invasive install in under 30 min
- Compatible with all pipe materials (copper, PEX, PVC, multilayer)
- 20+ year lifespan, zero consumables
Frequently asked questions — Île-de-France
What is the water hardness in Île-de-France?
In Île-de-France, water hardness ranges from 25 to 40 °fH depending on the water source. The value varies locally — your water bill shows the exact hardness for your municipality.
Why is the water harder in Île-de-France?
Hardness comes directly from local geology in Île-de-France. Water flowing through limestone, sedimentary or chalk rocks dissolves calcium and magnesium ions, which form limescale.
How do I know if limescale is affecting my system?
Early signs: visible scale on faucets, white marks on dishes, lower shower pressure, rising water-heater electricity bills. Above 25 °fH, scaling becomes unavoidable without protection.
Do I need a salt softener for very hard water?
No. Salt softeners add sodium to your water (not recommended above 200 mg/L per ANSES) and consume 30–60 kg of salt per year. LIMPEO treats limescale with an electromagnetic field — no salt, no resin — and preserves drinking water quality.
Does LIMPEO really work on very hard water?
Yes. Independent peer-reviewed studies (Trinity College Dublin 2000, Jozef Stefan Institute 2001, MDPI 2024) confirm electromagnetic treatment alters calcium carbonate crystallization, converting calcite (scaling) into aragonite (non-adherent).