CLEARMASTERS
repair engineers
call-outs
after every visit
and tankers
in drainage
The range
Which Marsh plant do you have?
Marsh Industries make a wide range of plants, sized for the number of people they serve. The ones we see most are:
Ensign Standard and Ensign Ultra: three-stage plants with no moving parts inside the tank. The Ultra adds a quieter compressor with a low-pressure alarm and a final filter.
Your plant will also need regular desludging, and we can do both on the same visit. We service the other main makes too, including WPL Diamond and Klargester.
We do this work across Surrey, West Sussex, East Sussex, Kent, Hampshire and London, with tankers and engineers in each area most days.
Shallow Ensign: a lower version for sites where digging deep is difficult.
Uni:Gem: a conversion unit that adds aeration after an existing septic tank, so it can meet today’s rules for discharging to a ditch or stream.
How it works
How a Marsh Ensign works
Bacteria live on small pieces of media that tumble around in the aeration chamber. Hover over or tap the numbers to see each part.
- 1InletWastewater from the property flows in.
- 2Primary settlement chamberSolids settle to the bottom as sludge. This is what’s removed when the plant is desludged.
- 3Aeration chamber with moving mediaBacteria live on small pieces of media that tumble around in the bubbling water, cleaning it.
- 4Compressor and diffusersThe only moving part. Marsh recommend cleaning the filter and checking the diaphragms every year.
- 5Final settlement chamberLoose bacteria settle out before the water leaves.
- 6OutletTreated effluent flows out to a drainage field or watercourse.
Septic tank conversions
Got a Marsh conversion unit?
Since 2020, septic tanks that discharge straight into a ditch, stream or river have had to be upgraded or replaced. A Uni:Gem is one way to do it.
How it works
Effluent from your existing septic tank flows into the Uni:Gem’s aeration chamber, where bacteria on moving media treat it, then into a settlement chamber before it’s discharged.
What it needs
Like an Ensign, it has a compressor that needs regular care, and the septic tank in front still needs desludging.
Why servicing matters
It’s there to bring your discharge up to standard, so it needs to be working properly.
Keep a record
A service record shows your upgraded system is being looked after.
The rules
What the rules say about servicing
On the day
What happens on a Marsh service
We check the compressor
Clean the filter, check the diaphragms and, on an Ultra, test the low-pressure alarm.
We check the aeration
Make sure the diffusers are bubbling evenly and the media is moving.
We check the treatment
Look at the chambers, measure the sludge and check the effluent.
We report back
Explain what we found and when the next desludge is due.
Why Clearmasters
Why choose us for your Marsh plant?
We service Marsh plants and conversion units across the South East, and we can desludge the plant, or the septic tank in front of a Uni:Gem, on the same visit.
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.
Service and desludge together
One visit for the servicing and the emptying.
What our customers say
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Scores as of September 2026
Questions answered
Marsh servicing FAQs
How often should a Marsh Ensign be serviced?
Once a year for a domestic plant. Marsh recommend cleaning the compressor filter and checking the diaphragms annually.
How often does an Ensign need desludging?
Marsh say domestic Ensign plants from 6 to 35 people should be desludged annually or as required. We’ll measure the sludge on every service.
Does a Uni:Gem need servicing?
Yes. It has a compressor and aeration system that need regular care, and the septic tank in front of it still needs emptying.
What’s the difference between the Ensign Standard and Ultra?
The Ultra adds a quieter compressor with a low-pressure alarm, an electrical box with an RCD, a final filter and a heavy-duty lid.
Is desludging part of a service?
No, desludging is done by one of our tankers and charged separately, but we can arrange it for the same visit. Your engineer will measure the sludge and tell you when it’s due.
Is servicing a legal requirement?
The Environment Agency’s rules say your plant must be operated in line with the manufacturer’s specification, and should be regularly maintained in line with their instructions by someone competent. If your discharge causes pollution, the first question you’ll be asked is when it was last serviced. A regular service is the simplest way to stay on the right side of the rules.
Got a different question? Call 03333 233566 or send us a message. You can also read the rules on GOV.UK.
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.