How many portable toilets does a construction site need?

The legal requirement

Under the Construction (Design and Management) Regulations 2015 (CDM 2015) and HSE guidance, all construction sites must provide adequate welfare facilities. The specific requirements for toilets are set out in Schedule 2 of the CDM Regulations.

The baseline requirement is one toilet per 7 workers where facilities are flushed to mains drainage, or where this isn't possible, chemical toilets in sufficient numbers. In practice, for most construction sites using portable chemical toilets, one unit per 7 workers is the accepted standard.

Simple calculation guide

Male and female workers

Where both male and female workers are present, the CDM Regulations require separate facilities where reasonably practicable. In practice on most sites, this means separate male and female portable toilet units positioned in different locations, or a welfare unit with separate male and female toilet provision.

What happens if you don't comply?

The HSE takes welfare provision seriously. Inspectors visiting sites can issue improvement notices requiring immediate action, prohibition notices stopping work, and in serious cases, prosecution. The Health and Safety at Work Act 1974 provides for unlimited fines for breaches of welfare requirements.

Beyond legal compliance, inadequate toilet facilities have a direct impact on productivity, worker wellbeing and your reputation as a contractor. Workers who have to leave site to find facilities waste time and resent employers who don't provide basic welfare.

Do I need a welfare unit or just portable toilets?

For small domestic builds of short duration, standard portable chemical toilets usually suffice. However, the CDM Regulations also require facilities for rest, eating, washing and changing clothes. For any significant construction project, a welfare unit combining toilet, canteen and drying room facilities is the complete solution and protects you from wider welfare compliance issues.

Not sure what you need? Tell us about your project and we'll advise on the correct welfare provision — free of charge and with no obligation.