Rennes
France · Europe
The water
172 mg/LHard
Source: Ministere de la Sante SISE-Eaux via Hub'Eau (Eaufrance) · Published figure. Hardness counts dissolved calcium and magnesium in the water; it is the number your hair meets in the shower.
What hard water does to hair
Minerals start to coat the strand: dullness, tangling, colour fade. Chelating (detox) washes enter the routine.
The washing routine for Rennes
Build the routine around a detox (chelating) wash about every fourth wash, with gentle washing between detox days. Follow every wash with conditioner; at this level the cuticle roughens quickly and colour-treated hair fades sooner.
Climate, from recent records (Open-Meteo, ERA5 2015-2024): July is the warmest month, averaging 24°C by day, and humidity peaks in December at about 88% on average. In the humid months, frizz is the main event; anti-humidity styling matters more than wash frequency.
Plugs and power for your tools
Sockets: Type C and E. Supply: 230 V, 50 Hz.
Full sockets by the sink are standard (kept outside the 60 cm splash zones around the bath and shower, and RCD protected, under the IEC 60364 zone rules).
A 120 V only dryer or styler (North American) will burn out on this supply, and a plug adapter does not change voltage. Check the label for dual voltage (100-240 V) before you plug in.
Plug, voltage and frequency: IEC World Plugs and national standards.
Plan Rennes properly
The trip planner turns this water profile into a wash plan for your hair type, a chosen kit and a packing list, month by month.