Water restrictions relaxed in Yvelines

Water usage restrictions have been eased in the Yvelines since Saturday, October 31, 2026. The Seine zone, which includes Versailles, Poissy, and Mantes-la-Jolie, moves from reinforced alert to alert. The other five areas of the department are now under vigilance, but the rules applicable to individuals vary depending on their commune.

New decree replaces previous one

Signed on October 30, prefectural decree number 78-2026-10-30-00001 replaces that of October 9. It reduces constraints on domestic and professional water use after an improvement in hydrological indicators. The Seine zone remains, however, subject to specific prohibitions, notably for watering, washing vehicles, and filling private pools.

Seine zone includes key communes

The Seine zone includes densely populated communes in the department: Versailles, Le Chesnay-Rocquencourt, Saint-Germain-en-Laye, Sartrouville, Houilles, Poissy, Les Mureaux, and Mantes-la-Jolie are listed in the annex to the decree. In this area, the level moves to simple alert, after several weeks of reinforced alert.

Watering restrictions apply between 11 a.m. and 6 p.m.

For residents of these communes, watering vegetable gardens, lawns, flower beds, and green spaces is now prohibited between 11 a.m. and 6 p.m. This time frame is included in the regulatory annex, which applies to direct withdrawals from the natural environment as well as water from the public network. Sports fields and race tracks are also affected by this time restriction.

Other water use prohibitions remain

Other prohibitions remain in place. Washing vehicles at home remains prohibited for private use. Car washes may operate on tracks equipped with high pressure, systems recycling at least 70% of the water, or portals using an economical program, according to the conditions outlined in the decree.

Private pool filling and cleaning rules

Filling a private pool larger than one cubic meter remains prohibited, except for upgrades or sanitary needs. Cleaning facades, roofs, and sidewalks remains reserved for interventions carried out by a local authority or a professional cleaning company. These rules are detailed in the usage table attached to the prefectural decision.

Other zones move to vigilance level

The change also affects the Center and West zones, which move from alert to vigilance. They join the South-West, South-East, and East areas, which have already been classified at this level. For these five sectors, the departmental plan provides awareness campaigns about water conservation rather than the general prohibitions applied to the Seine zone.

Saint-Germain-de-la-Grange confirms vigilance status

The commune of Saint-Germain-de-la-Grange confirmed this classification in a municipal information published on November 2. It reminds residents that its territory has been under vigilance since October 31 and calls on residents to conserve the resource.

Zones follow hydrological boundaries

The boundaries of the zones follow a hydrological division and do not necessarily correspond to the boundaries of intercommunalities. To find out the situation at one's address, the public service VigiEau allows consultation of current restrictions according to location and type of use. Municipal decrees must also be taken into account when they exist.

Agricultural exemptions remain

The decree maintains provisions adapted to certain agricultural productions. Farms designated by state services, notably in horticulture, vegetable crops, and fruit tree cultivation, may benefit from a derogation for sprinkler irrigation, up to 300 cubic meters per hectare and per week. The volumes used must be recorded and a report submitted to the departmental territory director upon returning to normal conditions.

Measures may be adjusted as needed

The prefect retains the possibility of modifying the measures based on the evolution of watercourses and aquifers. The text sets the end of the awareness measures it provides by no later than December 31, 2026, unless adapted by a new decree. In the Seine zone, residents must continue to comply with alert restrictions as long as this classification remains applicable.