Site welfare units for UK construction sites

• Toilets

  Provide sufficient suitable, readily accessible toilets. Prefer flushing units where possible. Agree the actual number, use, cleaning, emptying, toilet paper and sanitary waste arrangements.

• Washing facilities

  Washing facilities belong beside toilets and near required changing rooms. They must include clean hot and cold, or warm, water, with running water so far as reasonably practicable, cleaning products and a way to dry. Provide showers where the work or health risks require them.

• Showers

  Provide suitable showers where the nature of the work or health risks require them. Assess contamination, washing procedures, hot or warm water, drainage, privacy and any specialist decontamination needs.

• Privacy and shared facilities

  Shared toilets must each be in a room that locks from inside, separate from any urinals. Hand, forearm and face washing can be shared; showers need separate provision or a lockable room for one person at a time.

• Changing and clothing storage

  Changing rooms are required where workers need special work clothing and cannot reasonably change elsewhere for health or propriety reasons. Provide seats, separate rooms or separate use by men and women where needed, and drying facilities where necessary. Provide secure storage for clothing and personal effects where needed.

• Eating and rest

  Provide accessible rest rooms or areas with enough tables and seats with backs for simultaneous users, arrangements to prepare and eat meals, and a way to boil water. Maintain an appropriate temperature. Provide for pregnant or nursing workers to rest lying down where necessary.

• Drinking water

  An adequate supply of wholesome drinking water must be readily accessible. Mark drinking supplies where health or safety requires it. Provide suitable drinking vessels unless people can drink easily from a water jet.

• Layout and access

  Position facilities so workers can reach them readily throughout their working hours. Include remote work areas, safe pedestrian routes, servicing access and replacement provision during relocation.

• Heating

  Maintain an appropriate temperature in rest areas. Specify suitable heating and safe installation, including any risks from fuel-burning equipment.

• Ventilation

  Provide sufficient ventilation for washing rooms and suitable ventilation for toilets and occupied welfare areas. Keep heaters, air inlets and vents maintained and unobstructed.

• Lighting and servicing

  Provide lighting for toilets, washing areas and access. Assign checks, cleaning, consumable replenishment and fault response before use; increase service frequency where conditions require it.

For 18 workers, the one-per-seven guidance gives 3 portable chemical toilets, rounded up, for a 40-hour week with weekly emptying assumed.

This illustrates HSE's cited guidance for portable chemical toilets, with a 40-hour working week and weekly emptying. It is not a statutory CDM minimum, a flushing-toilet calculation or proof that the facilities are sufficient. Longer use, shifts, servicing, privacy and the work may require more provision. For Northern Ireland, use Schedule 3 and confirm the arrangements under HSENI guidance. This illustration is separate from the quotation checklist.