TL;DR
A homebuyer drainage survey looks at what a standard building survey never touches, which is the underground pipework. That matters in Brighton and Hove area, Worthing area and Shoreham-by-Sea area, where many homes are older and have been extended. A camera survey can reveal a hidden defect and show who may be responsible for which pipe. It also gives you something concrete to raise before you exchange. Request a free quote online to arrange one ahead of a purchase.
Why older homes need a dedicated drainage check
A standard homebuyer or building survey is a visual inspection of the parts of a property that anyone can reach. It does not cover the drains, so whatever happens underground stays invisible to a buyer who relies on that report alone.
That gap matters more in older areas, because many properties here predate modern drainage design. Decades of extensions and new bathrooms may have been tied into the original pipework in whatever way suited the builder. As a generic rule, the pipe serving only your property inside your boundary is yours. Since 2011, many shared drains and the sections beyond the boundary became the water company's responsibility. A survey will not settle ownership on its own, so check the details with Southern Water. A dedicated drainage survey at least shows the pipe's condition before you commit.
What the survey involves
A survey uses a waterproof camera fed into the drain through an existing manhole or chamber. It records the inside of the pipe as it goes, so cracks, shifted joints, roots and corrosion all show up. The engineer then grades the defects from minor to serious, which gives you a consistent way to judge how urgent each one is.
The report also includes a drain map. It shows the pipe direction and material, the position of chambers and any notes about shared drainage. Your solicitor or conveyancer can use that factual record to raise the right questions before exchange, because it replaces vague impressions with evidence. We cover what the written report holds in more detail in our guide to what a CCTV drain survey shows.
Build-over and shared-drain checks
Older terraces and converted homes often have drains running under later additions, such as an extension or garage. Building over a drain can need the water company's agreement. Therefore, if you see signs of a build-over, ask the seller whether anyone sought permission, and check with Southern Water.
A survey can show physical signs, such as concrete around the pipe or a slab edge sitting on it. That gives you grounds to ask questions early, since the answer matters more before exchange. You would rather hear the answer before you exchange than after you move in.
Shared drainage is the other common trap. Several neighbouring houses can share one drain before it reaches the public sewer. Original plans often go missing, so it is not always obvious which sections are private. A survey shows where shared sections exist. For more on this, see our piece on blocked drains and whose job it is.
Buying along the coast
The same principle applies from Worthing area to Lancing area and on to Shoreham-by-Sea area. Wherever a building has been extended or re-plumbed more than once, a viewing tells you little about what happens underground. Taps that run and a toilet that flushes do not prove the drains are sound, because the problems sit underground. That is why a dedicated survey is worth having before you commit.
If a home has a lower-ground flat or a pumped toilet, ask extra questions. Our guide to basement flat drainage lists the points to check. To understand how a quote is built, read what affects CCTV survey pricing.
Making sense of the results
When you have the report, focus on the defect grades and any note about ownership or build-over. Minor findings are often fine to monitor, while serious ones need a plan. More serious defects may mean budgeting for repair work, and it is reasonable to ask for a written quote before you exchange. A major finding, such as a collapsed section, is worth raising with the seller. You can then negotiate on price or ask for a repair before completion.
If the report shows a drain under an extension with no record of agreement, ask Southern Water directly. With the facts in hand, your solicitor can work from evidence instead of assumptions. You can then decide whether to go ahead, renegotiate or walk away. If you are buying on this stretch of coast, request a free quote online.
Frequently Asked Questions
Do I need a drainage survey if I already have a building survey? Yes, if the property is older or extended. A building survey does not inspect underground drains, so this is a genuine gap.
What is the difference between a private drain and a public sewer? A public sewer is looked after by the water company, which is Southern Water here. A drain serving only your own property is generally yours to maintain, so check the details for your home with Southern Water.
What if the survey shows a possible build-over? Raise it with the seller before exchange, and ask Southern Water how to put it right. Your solicitor can advise on the legal side.
Can I use the report to negotiate on price? Often, yes, because a documented defect with a clear grade gives you a factual reason to ask for a repair or a lower price.
