The treatment plant faults that come up most in Kent, which are cheap and which are not, what drives a repair bill, and the servicing that prevents them.
Across Kent, many rural homes, farms and small businesses rely on a sewage treatment plant rather than the public network. Unlike a septic tank, a plant is machinery. It has a blower or a motor, bearings and controls, it runs every hour of every day, and parts on it wear out. This guide covers the faults KP Cesspool Services see most often on plants in Kent, roughly how serious each one is to put right, what drives the cost, and the servicing that stops most of them happening at all. Repairs and service plans are on our treatment plant servicing and repairs page.
Why plant faults vary so much in cost
The same symptom can mean a five minute fix or a major repair. An alarm can be a tripped fuse or a burnt out motor. A smell can be a blocked air filter or a plant that has stopped treating altogether. So the honest answer to "what will it cost" is that it depends on the fault, the make of plant and how long it was left. What follows groups the common faults from the cheapest to put right to the most expensive, so you know what you might be facing.
Usually minor
A tripped supply. Plants share a circuit with everything else on some properties, and a damp connection or a power cut can trip it. If it resets and stays on, that may be the end of it. If it trips again, there is a fault to find.
A clogged air filter. Blower driven plants draw air through a filter that gradually clogs. Less air means less treatment and, eventually, a smell. Cleaning or replacing the filter is part of every service and costs little.
A stuck float switch. Plants that pump their treated water out, and batch plants that work in cycles, use float switches to sense the level. One that sticks leaves the plant brimming or the alarm sounding even though everything else works.
A blocked pipe. Wipes, fat and sanitary products block the pipe into the plant or the pipe out of it. Clearing it with high pressure jetting is usually straightforward.
Moderate
Blower diaphragms or vanes. The blower on an aerated plant runs constantly, and its diaphragms or vanes wear out in time. Replacing them is a routine repair. Leaving a worn blower running weakly lets the plant slide into poor treatment.
Diffusers. The diffusers that spread air through the middle chamber can block or break, leaving dead zones where waste is not treated. Replacing them means getting into the chamber, so it takes longer.
Pumps. Where a plant pumps its outlet uphill to a drainage field or a ditch, the pump is a wearing part. A failed pump stops the plant discharging.
Major
A failed blower or motor. When the whole unit fails rather than a wearing part inside it, the replacement is a significant cost, and the plant stops treating until it is done.
Disc plant drive faults. On rotating disc plants such as the Klargester BioDisc, the motor, gearbox and main shaft bearing carry the load. A failed bearing or gearbox is one of the more expensive repairs, and an unevenly loaded disc pack wears them faster. A change in the sound of the motor is often the first warning.
A damaged tank. A cracked shell, failed internal partitions or a tank that has lifted in waterlogged ground can be beyond repair. At that point the money is usually better spent on a replacement plant than on patching.
What drives the price of a repair
Besides the part itself, three things move the cost. The make and model, because parts for some plants are easier to source than others. Access, because a plant at the end of a long garden, or one that has to be emptied before anyone can work in it, takes longer. And timing, because a fault caught at a service is cheaper than the same fault after it has stranded you and caused a second one. We price the repair before we start, so there are no surprises.
When this guide was first written in late 2025, a routine annual service in Kent typically ran between £150 and £300, depending on the plant. Ring for a current price for yours.
The servicing that prevents most of it
Nearly every fault above gives a warning first. A blower that is starting to fail runs noisily or delivers less air, a bearing gets louder, a filter clogs gradually. A service every six to twelve months, as most manufacturers ask, catches them while they are cheap. Skipping services can also void the warranty. What to expect from treatment plant servicing walks through a visit, and how long a treatment plant lasts explains what wears and when.
Your legal duty
The General Binding Rules require a plant to be maintained by someone competent and repaired or replaced if it is not in good working order. A broken plant is still discharging, and what it discharges is no longer treated properly, so a fault left unrepaired is a pollution risk the owner is responsible for. The Environment Agency can take action if it causes harm. Keep a record of every service and repair, because you will need it when you sell.
When repair stops making sense
If a plant needs a major repair most years, or the tank itself is failing, a replacement is usually the better value, and we will say so plainly. Our treatment plant work across Kent covers servicing, repairs and replacements, and the treatment plant installation page covers what a replacement plant involves.
Getting a fault looked at
If your plant has alarmed, stopped or started to smell, ring us rather than waiting. KP Cesspool Services has over twenty years' experience with private drainage across Kent and East Sussex, and you can read our reviews on Checkatrade. Call 01233 720725, email kpcesspoolservices@hotmail.com, or contact us.
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