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The basics
What is a cesspit?
Whether you own a property with off-mains drainage, or you're looking to buy or rent one, it's worth knowing what kind of system you have and how to look after it.
Where the site allows it, some cesspit owners switch to a sewage treatment plant to cut down on emptying. We also empty septic tanks and holding tanks.
We do this work across Surrey, West Sussex, East Sussex, Kent, Hampshire and London, with tankers and engineers in each area most days.
A cesspit, also called a cesspool, is a sealed holding tank. Waste from your toilets, sinks, bath and washing machine flows in through the inlet, but there's no outlet. Nothing is treated and nothing drains away, so everything stays in the tank until a tanker empties it.
That's the big difference from a septic tank, and it's why a cesspit needs emptying far more often. How often depends on the size of the tank, how many people live in the house and how much water you use.
Fill-up calculator
How quickly will my cesspit fill up?
Move the slider to the number of people in the house and pick your cesspit's size to get a rough idea of how often it will need emptying.
Not sure of the size? We can usually tell you after the first empty. For reference, Building Regulations guidance says a new cesspit should hold at least 18,000 litres (about 4,000 gallons) for two people, plus 6,800 litres for each extra person.
More than one property on your cesspit? The sums get a little more complicated, but not impossible. Give us a call with the details and we'll work it out with you.
Why it matters
What happens if a cesspit is left too long?
A cesspit can only hold so much. Once it's full, your drains slow down and back up, toilets stop flushing properly, and eventually the tank overflows into the garden.
Sewage overflowing or leaking into the ground is a pollution risk, and it's the owner's responsibility to stop it happening. A cesspit should be watertight and emptied before it's full.
Many of our cesspit customers are on a regular emptying schedule, so a tanker turns up before the tank fills, without you having to remember to call.
Signs your cesspit is full
- Sinks, showers and toilets draining slowly
- Gurgling from the drains
- Bad smells around the tank or drains
- The high-level alarm going off
- Wet ground or sewage around the tank lid
On the day
What happens when we empty your cesspit
We send the right tanker
Our tankers range from 2,000 to 4,000 gallons. Tell us the size of your cesspit and about any tight access, and we'll send one that fits.
We empty it completely
We pump the tank out fully, including the solids at the bottom, so you get the most out of every empty.
We check it over
If we spot signs of a leak, rainwater getting in or a damaged lid, we'll tell you in plain English.
You get a waste transfer note
Proof your waste was removed by a registered carrier and disposed of properly. Keep it with your records.
Why Clearmasters
Why choose us to empty your cesspit?
Cesspits need emptying often, so you want a company that turns up when it says it will. You'll get a friendly office team who know cesspits, and engineers who take the time to do the job properly.
Ask us a questionAlways on hand
Routine visits booked at a time that suits you, and 24/7 call-outs when something goes wrong.
Advice from people who know
Our office team can talk you through your system, your options and the rules, or simply get you booked in.
Trained, friendly engineers
Our engineers work with minimal disruption and are happy to answer any questions while they're with you.
Regular schedules
Set up regular emptying and we'll book you in before your cesspit fills, so it's one less thing to think about.
What our customers say
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Questions answered
Cesspit FAQs
How often does a cesspit need emptying?
It depends on the size of the tank, how many people live in the house and how much water you use. Some cesspits need emptying every few weeks, others every few months. Use the calculator above for a rough idea, or call us and we'll help you work out a schedule.
How do I know my cesspit needs emptying?
Don't fancy lifting the lid to look? We don't blame you. Slow drains, bad smells and gurgling pipes are the most common signs, and if your cesspit has a high-level alarm it will tell you. If you're not sure, we can check.
What happens if I don't get my cesspit emptied?
Your drains will slow down and back up, and eventually the tank will overflow into the garden, which is unpleasant and a pollution risk.
I'm planning an extension. Do I need to think about my cesspit?
Yes. More bedrooms usually means more people and more wastewater, so your cesspit will fill faster. It may also be a good time to look at replacing it with a treatment plant, which doesn't need emptying anywhere near as often.
I think my cesspit is leaking. What should I look for?
Signs include the tank needing emptying less often than it used to, wet or sunken ground around it, and grass growing faster or greener near the tank. It's also worth checking the opposite: if it fills much faster than it should, rainwater or groundwater may be getting in. Either way, get our team out to take a look.
Can I replace my cesspit with something more modern?
In most cases, yes, depending on your ground and the space you have. A treatment plant costs more to install but needs emptying far less often, so it can save a lot in the long run. We can look at your site and talk you through the options.
Does a cesspit need to be registered?
No. You don't need to register a cesspit or get a permit, because nothing is discharged from it. You do need to keep it watertight and have it emptied before it overflows. Installing a new cesspit needs building regulations approval and usually planning permission.
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.