Welfare facilities calculator

What the law actually requires

Welfare on construction sites is governed by Schedule 2 of the Construction (Design and Management) Regulations 2015. Every site must have it, regardless of size or duration, and it must be in place before work starts and maintained throughout. Schedule 2 sets the duties in words rather than numbers: it requires "suitable and sufficient" toilets and washing facilities, drinking water, changing rooms and lockers where needed, and rest facilities — but it never says how many toilets you need for a given headcount.

The Schedule 2 baseline (qualitative duties)

• Toilets — suitable, sufficient, ventilated, lit, kept clean, and separate for men and women unless each toilet is in its own lockable room.
• Washing facilities next to every toilet and any changing room, with clean hot and cold (or warm) running water so far as reasonably practicable, plus soap and a means of drying. Showers where the work or health reasons require them.
• Drinking water — an adequate supply of wholesome water at accessible places, with cups unless it is a drinking jet.
• Changing rooms and lockers where workers must wear special clothing and cannot change elsewhere — with seating and a means to dry clothing.
• Rest facilities — rest rooms or areas with enough tables and seating, a means of heating food and boiling water, and protection from the weather.

Where the numbers come from

Because CDM gives no figures, the construction industry applies the scale in BS 6465-1:2006, which HSE's construction welfare guidance points to. The headline rule is one water-flushed toilet and washbasin per seven people where portable units are emptied weekly. For a known men/women split, the men's WC count can be lower because urinals share the load. Chemical or non-flushing toilets, and units serviced less often, need a more generous ratio. Those numbers are a benchmark, not law — provide more where the work, conditions or servicing interval call for it.

Mains water, duration and dirty work

You must provide running washing water even without a mains connection — a bowser, heater or self-contained welfare unit can do it. Longer projects should move to permanent or semi-permanent welfare connected to mains water and drainage where practicable, while short or transient work can use a mobile unit (or, only where genuinely impractical, agreed access to nearby public facilities). Where the work involves hazardous substances or is very dirty — contaminated land, dusty demolition — Schedule 2 requires showers, kept separate from the main washing facilities for the most hazardous work.

Sources: Construction (Design and Management) Regulations 2015, Schedule 2 (legislation.gov.uk), and HSE construction welfare guidance CIS59 (hse.gov.uk/pubns/cis59.pdf), which cites BS 6465-1:2006.