How Often Should You Get a Drain Survey? A Guide by Property Type

There is no fixed interval for surveying the drains at a house. Most homes only need a CCTV drain survey when something prompts one: a purchase, repeated blockages, a smell, building work near the drains or an insurance claim. A planned re-survey makes sense once a survey has found a defect worth watching, or where the drains serve a building with heavy use, such as a block of flats, a restaurant or a commercial site. How often depends on what the last survey found, not on the calendar.

Is there a rule for how often you should get a drain survey?

No. There is no legal requirement or industry standard that says a domestic drain must be surveyed every so many years. If your drains run freely and nothing has changed, a survey on a timetable is usually money you do not need to spend.

The more useful question is what would make a survey worth doing now. A survey answers a specific question about the inside of the pipe: whether it is cracked, displaced, blocked by roots, holding water or connected where it should be. When nobody is asking that question, the footage mostly confirms what the free-running drain already tells you. Commercial and multi-occupancy buildings are different, and are covered below, because problems there affect more people and cost more when they are found late.

When a house needs a drain survey

A house needs a survey when a decision depends on the condition of the drains, or when symptoms suggest something inside the pipe has changed. These are the usual triggers:

• Buying a property. Especially an older London house with clay drains, large trees nearby or an extension built over the drain run. Our guide on whether to get a drain survey when buying a house covers when it is worth it.
• The same drain blocking more than once. One blockage can be bad luck. A second in the same run usually has a cause, such as a displaced joint, roots or a dip that holds debris.
• Smells, damp or subsidence signs. A drain smell that returns after cleaning, damp low on a wall near a drain run or cracking that could point to a leaking pipe.
• Building work. Before an extension, basement or new bathroom connects to or sits near existing drains, and again afterwards if the work could have damaged them.
• An insurance claim. The insurer will usually want footage and a report before deciding who pays for a repair.
• After a repair. A survey at the end of the job shows the repair was done and records its condition on day one.

If none of these apply, you probably do not need one. A reputable drainage firm should say so rather than sell you a survey you have no use for.

How often to re-survey after defects are found

If a survey finds a defect that does not need repairing yet, the report should say when to look again. The interval depends on the type of defect, how serious it is and what the drain carries.

Survey reports grade defects by severity, usually on a scale where 1 is minor and 5 is serious. Our explainer on how to read a CCTV drain survey report covers the grades and codes. As a rough guide:

The table is a starting point, not a rule. A moderate defect under a kitchen extension or next to a party wall deserves more attention than the same defect in a rainwater run at the end of a garden. What the drain carries matters too: a kitchen drain that takes fat will silt up at a defect faster than one carrying rainwater. When you compare surveys over time, ask for the same runs to be surveyed from the same chambers, so that defects can be matched by position and you can see whether they are getting worse.

After a repair or relining

Every repair should end with a survey, and that completion footage is the baseline for any later check. After that, a repaired drain does not need regular surveying unless it gives trouble.

The completion survey should show the repaired section, the joints either side and any side connections that were reopened. Keep the footage and report with your property documents. If the drain blocks or smells again, a new survey can be compared against it to show whether the repair has failed or a new problem has started elsewhere. That comparison is also what a contractor or insurer will want to see if you ask them to put the problem right under a guarantee or a claim.

Landlords, blocks of flats and managing agents

Buildings where several households share the drains are worth surveying on a plan rather than waiting for a failure. A baseline survey, then targeted re-surveys of the runs that cause problems, is usually the sensible pattern.

A single-household let is closer to a private house. A survey before a new tenancy is sensible if the drains have a history of problems, and after any blockage that suggests a defect, but not every year as a matter of course. Blocks of flats are different. The shared stacks, underground runs and any pumps serve everyone, and a blockage or collapse affects several flats at once. Survey the whole shared system once to create a baseline with a plan of the runs. After that, re-survey problem runs on the interval the report recommends and look again after any significant building work. Our guide to drain surveys for blocks of flats sets out what a managing agent should ask for.

Commercial premises

Commercial drains usually need more frequent inspection than domestic ones because of what goes into them. The right interval comes from the use and the history of each run, set out in a maintenance plan, not from a single rule.

A restaurant kitchen drain carrying fat, a food production site or a busy washroom block will show problems far sooner than an office's surface water drains. The practical approach is a full baseline survey, repairs where they are needed, then planned cleaning with periodic camera checks of the runs that caused trouble. Leases, insurers and some local authority conditions may set their own inspection requirements, so check them before settling a schedule. Where a maintenance contract includes camera inspections, it should say which runs are surveyed, how often and what report you receive.

When another survey is the wrong answer

If you already have a recent survey and the drains have not changed, a new survey rarely adds anything. It is also the wrong first step when a drain is actively blocked and backing up.

A blocked drain needs clearing first. The camera cannot see through standing water or waste, and the clearance itself often shows the cause. A survey afterwards makes sense if the blockage was unusual or keeps returning. Equally, if a survey from a year ago recorded a defect and a quote to fix it, and nothing has changed since, you normally need the repair, not more footage. Where you are unsure whether a new survey is justified, send us the old report and a description of what has changed. We will tell you whether a fresh CCTV drain survey will answer anything the old one did not.