CLEARMASTERS
repair engineers
call-outs
after every visit
and tankers
in drainage
The basics
What is a confined space?
A confined space is somewhere enclosed where dangerous gases, a lack of oxygen, rising liquid or difficult access could seriously harm someone. Septic tanks, treatment plants, pump station wet wells, deep manholes and sewers all count.
Our teams work inside pump stations, treatment plants and sewers, so the same crew can clean, inspect and repair in one visit.
We do this work across Surrey, West Sussex, East Sussex, Kent, Hampshire and London, with tankers and engineers in each area most days.
Sewage gives off gases, like hydrogen sulphide, that can overcome a person in seconds. That’s why entering one is covered by the Confined Spaces Regulations 1997, and should only ever be done by a trained team with the right equipment and a rescue plan.
Safety first
How a confined space entry is set up
Every entry is planned, but a typical set-up looks like this. Hover over or tap the numbers to see each part.
- 1Tripod and rescue winchSet up over the opening so the engineer can be lifted straight out if anything goes wrong.
- 2Harness and lineThe engineer inside is attached to the winch at all times.
- 3Gas monitorChecks for oxygen, flammable gas, hydrogen sulphide and carbon monoxide before and during entry.
- 4Top personStays at the opening throughout, watching the monitor, keeping contact and ready to start a rescue.
- 5Forced ventilationA fan blows fresh air into the chamber to keep the atmosphere safe.
- 6BarriersKeep the public, pets and vehicles away from the open chamber.
On the day
What’s involved in a confined space entry
Assess and plan
We look at the job, the risks and whether entry can be avoided, then write a safe system of work and a rescue plan.
Test and ventilate
The atmosphere is tested before entry and ventilated with fresh air.
Enter and work
The engineer enters on a harness and line, with a top person watching the gas monitor throughout.
Exit and report
Everyone out, equipment cleaned and a report of the work done.
Why Clearmasters
Why choose Clearmasters?
Our engineers and most of our tanker drivers hold current confined space entry certificates. We only enter a confined space when we have to, and when we do, it’s planned, equipped and done by a trained team.
Ask us a questionAlways on hand
Planned servicing at a time that suits you, and 24/7 call-outs when something goes wrong.
Straight answers
We explain what we found in plain English, and give you honest advice on what needs doing now and what can wait.
Trained engineers
Our engineers hold current confined space entry certificates and work on treatment plants, pump stations and drainage every day.
A team, never one person
There’s always someone at the top, ready to start a rescue.
What our customers say
Checkatrade
From 134 reviews · Read them
From 63 reviews · Read them
Scores as of September 2026
Questions answered
Confined space FAQs
What counts as a confined space?
Any enclosed space where there’s a serious risk from gases, lack of oxygen, rising liquid or difficult access. Septic tanks, treatment plants, pump station wet wells and deep manholes all qualify.
Can I go into my septic tank or pump station myself?
No. Please don’t. The gases in a sewage tank can overcome someone very quickly, and many people who die in confined spaces were trying to rescue someone else. Call us instead.
Are your engineers trained?
Yes. Our engineers and most of our tanker drivers hold current confined space entry (CSE) certificates, and work to a safe system of work with gas monitoring and rescue equipment on every entry.
What equipment do you use?
Gas monitors, forced ventilation, a tripod and rescue winch, harnesses and lines, and barriers around the opening.
Do you work on domestic sites?
Yes. Many of our entries are at homes, inside septic tanks, treatment plants and pump stations.
Got a different question? Call 03333 233566 or send us a message.
Related services
Fully accredited & compliant
We're independently vetted and certified so you can trust who you're letting onto your site.
SafeContractor
Health & safety pre-qualification accreditation, verifying our processes meet recognised safety standards.
RISQS
Railway Industry Supplier Qualification Scheme — approved to work safely within the rail industry supply chain.
Achilles UVDB
Utilities Vetting Database membership, confirming we meet the utilities sector's supply chain standards.
Trading Standards Approved
Vetted and approved under the local authority's trusted trader scheme for honesty and fair dealing.
NADC Member
Members of the National Association of Drainage Contractors, the UK trade body for the drainage industry.
Registered Waste Carrier
Registered with the Environment Agency, so your waste is handled and disposed of fully within the law.