Septic tank & sewage guides
Straight answers on the rules, the costs and looking after an off-mains drainage system — written for homeowners, not lawyers.
Septic tank vs sewage treatment plant: what's the difference?
How septic tanks and package sewage treatment plants differ, what each one costs to run, and which you're allowed to install under the current rules.
The basicsSewage treatment plants: how they work, cost & installation
How a package sewage treatment plant works, what it costs to install, and why it can discharge to a stream where a septic tank can't.
Rules & complianceGeneral Binding Rules explained: 2020 septic tank rules
The Environment Agency's General Binding Rules for septic tanks and treatment plants, in plain English — with the 2020 ban on discharging to a watercourse.
Rules & complianceDo I need to register my septic tank?
Whether you need to register a septic tank with the Environment Agency, and when you need a permit instead under the General Binding Rules.
The basicsSeptic tank soakaways & drainage fields explained
What a septic tank drainage field is, how it works, and why a soakaway crate isn't a compliant substitute for one.
Rules & complianceDischarging to a watercourse vs to the ground: the rules
The difference between discharging treated sewage to a watercourse and to the ground, and what the General Binding Rules require for each.
Rules & complianceDo I need to replace my septic tank? (2026 UK rules)
Whether you need to replace or upgrade your septic tank depends on where it discharges. The plain-English answer under the 2020 rules, plus costs.
Rules & complianceBuying or selling a house with a septic tank
What matters about a septic tank when buying or selling: whether it meets the General Binding Rules, and what to check before the sale goes through.
CostsSeptic tank costs: emptying, installation and replacement
What septic tank emptying, installation, replacement and sewage treatment plants really cost in 2026 — typical ranges, and the four things that move the price.
CostsNew septic tank installation: process, rules & cost
The steps involved in installing a new septic tank, the General Binding Rules it has to meet, and what installation typically costs.
Maintenance7 signs your septic tank needs emptying
The warning signs that a septic tank is full or a drainage field is failing — and what to do before it becomes an expensive problem.
MaintenanceCommon septic tank problems (and what to do)
The most common septic tank problems — full tanks, failing drainage fields, blockages, smells and backing-up sewage — their usual causes and what to do.
MaintenanceLooking after your septic tank: maintenance dos & don'ts
The simple dos and don'ts that keep a septic tank working properly — what to flush, what to keep out, and whether additives actually help.
MaintenanceHow often should you empty a septic tank?
Most domestic septic tanks need emptying about once a year — but tank size and household size move that from 6 months to 2 years. How to work out yours.
Rules & complianceSeptic tank compliance certificates: what actually exists
There is no official septic tank compliance certificate in England. Here's what buyers' solicitors actually accept and what a compliance survey costs.
CostsSeptic tank replacement cost in 2026
Replacing a septic tank costs roughly £4,000–£12,000 in 2026. Like-for-like swaps, treatment plant upgrades, drainage fields and what moves the price.
CostsSeptic tank emptying cost in Cornwall (2026)
Septic tank emptying in Cornwall normally costs £150–£300 a visit — but quotes in August 2026 are running £300–£350. Why, and the cheapest time to book.
The basicsSeptic tank suppliers in Cornwall: a buyer's guide
Where to buy a septic tank or treatment plant in Cornwall: supplier routes, UK brands, supply-only vs supply-and-fit prices, and what to check first.
Rules & complianceCesspit vs septic tank: what's the difference?
A cesspit stores sewage; a septic tank treats it. Which one you have changes your emptying costs, your legal duties and what you must tell a buyer.
The basicsHow does a septic tank work?
How a septic tank works: solids settle, bacteria start breaking down waste, and the drainage field finishes the job. Why the ground matters most.
CostsPercolation tests: what they are and why you need one
A percolation test measures how fast your soil absorbs water — it decides whether a septic tank is viable and how big the drainage field must be.
Rules & complianceSeptic tank surveys: what they cover and when you need one
A drainage survey tells a buyer whether a septic system is compliant, serviceable and correctly sized — before contracts. What's checked and the cost.
MaintenanceHow long does a septic tank last?
A well-maintained septic tank can last 30-40 years — but the drainage field usually fails first, often within 15-25 years. What sets the lifespan of each.
MaintenanceSeptic tank smells: causes and what to do
A septic tank shouldn't smell in normal use. What each smell means — inside, near the tank, or over the drainage field — and which need quick action.
Rules & complianceShared septic tanks: who is responsible?
Share a septic tank? Everyone connected is jointly responsible for compliance, whichever land it sits on. How costs, access and liability usually work.
Rules & complianceDo you need planning permission for a septic tank?
Usually not — most domestic septic tanks fall under permitted development. But building regulations still apply, and Environment Agency rules are separate.
Rules & complianceIs my sewage pumping station mine or the water company's?
Many private sewage pumping stations transferred to the water company in October 2016. Two questions decide whether yours is South West Water's or yours.
The basicsPrivate sewage pumping stations explained
What a domestic sewage pumping station is, what's inside the chamber, why float switches fail, and what to do when the alarm goes off.
MaintenanceSewage pumping station servicing and repair costs
What it costs to service, repair or replace a domestic sewage pumping station — pumps, float switches, control panels — and when replacing beats repairing.
Rules & complianceDrains backing up: whose responsibility is it?
Blocked drain, backing-up toilet or overflowing manhole — how to work out whether it's your pipe, a shared one, or the water company's, before you pay anyone.
The basicsSouth West Water and your drainage if you're off mains
Enforcement action, discharge prosecutions and a squeeze on tanker disposal sites — what the South West Water situation means for off-mains homes.
Rules & complianceYour septic tank isn't compliant and you're selling: what now
The buyer's solicitor has raised the septic tank and it doesn't meet the rules. What actually has to happen, how long it takes, and how sales get over the line.
CostsWho pays to replace a septic tank — buyer or seller?
There is no legal default on who pays when a septic tank fails during a house sale. What actually decides it, and the four ways the cost gets split.
Rules & complianceWill a mortgage lender lend on a house with a septic tank?
Septic tanks rarely stop a mortgage on their own. What valuers flag, when a lender retains part of the advance, and how to clear it before it delays you.
The basicsBuying a house with a septic tank: what to check
The eight things to establish before exchanging on an off-mains property — where it discharges, who owns it, and what it will cost you if nobody knows.
CostsHow long does it take to replace a septic tank?
Realistic timings for a septic tank replacement — survey, percolation test, quotes and installation — and whether it can be done before a completion date.
MaintenanceSewage treatment plant servicing: cost, what's done, and the records buyers ask for
What an annual sewage treatment plant service involves, what it costs, why the General Binding Rules make it non-optional — and why the service records matter when you sell.
CostsSeptic tank grants: what help actually exists in 2026
There is no national grant for septic tank replacement in England. What does exist — catchment schemes, council initiatives, the s101A sewer-connection right — and how to check your area.
Rules & complianceThe drainage and water search when the house is off mains
What the CON29DW drainage and water search does and doesn't reveal when a property has a septic tank or treatment plant — and the questions your solicitor should ask instead.
The basicsDoes my house have a septic tank? How to find out
Five reliable ways to tell whether a property is on mains drainage or a private system — from your water bill to the manhole covers — and what to do once you know.
Rules & complianceThe septic tank failed the survey: should you still buy the house?
A failed septic tank survey is a negotiating position, not a dealbreaker. What each type of failure really costs, the four ways buyers handle it, and the traps — retention, indemnity, 'allowances'.