Whether you’re buying a new property, renovating, or troubleshooting an issue, drainage testing is a vital step in ensuring your system functions safely and efficiently. At London Drainage Services, we carry out thorough drainage testing to identify any defects or leaks before they cause bigger problems. But for many homeowners, understanding the results of a drainage test can be confusing. This guide explains what those results mean, how to interpret them, and what to do next.
What Is Drainage Testing?
Drainage testing is the process of checking the integrity of your drainage system to confirm that all pipework is watertight and performing correctly. It’s often required during new installations, property surveys, or before connecting to the public sewer system. These tests ensure your drains meet UK Building Regulations, especially Part H, which covers proper disposal of wastewater.
At London Drainage Services, we use a combination of methods including smoke tests, air tests, water tests, and CCTV inspections, to give you a complete picture of your system’s condition. Each test type reveals specific details about how your drainage performs.
Types of Drainage Tests
Drain Smoke Test
A drain smoke test is a quick and effective way to detect hidden leaks, cracks, or illegal connections within a drainage system. During this test, non-toxic smoke is blown through the pipe network, and any escaping smoke reveals points where air and therefore wastewater could leak out. It’s particularly useful for locating faults in hard-to-reach areas or confirming whether rainwater and foul water drains are correctly separated. At London Drainage Services, our engineers use professional-grade equipment to carry out safe and efficient smoke testing, helping homeowners identify issues early and avoid costly structural damage or odour problems in the future.
Air Test
An air test involves sealing the pipe system and introducing a small amount of air under pressure. A manometer measures pressure over time.
- A pass result means the pressure remains stable, showing there are no leaks.
- A fail result means pressure drops; often below the 75mm mark, indicating potential leaks, cracks, or faulty joints.
This type of drainage testing is quick and highly sensitive, making it ideal for identifying early signs of leakage before they escalate.
Water Test
A water test checks for leaks by filling the drainage section with water and monitoring for level changes. If the water level drops after a set period, it usually means there’s a defect somewhere in the system.
Unlike air testing, water tests are better suited for larger or longer drainage runs, as they assess how well the system retains water without pressure.
CCTV Drainage Survey
For the most detailed view, our engineers conduct CCTV drainage surveys. This test uses high-definition cameras to inspect internal pipe conditions. It identifies cracks, blockages, root intrusions, and joint misalignments.
CCTV surveys not only confirm leaks highlighted by other tests but also provide visual proof, helping property owners understand the exact issue and location.
Interpreting the Results
When you receive your drainage testing report, you’ll see results that indicate whether your system has passed or failed, along with specific findings. Here’s how to read them:
- Pass: Your drains are watertight and meet required standards. No further action is needed unless you plan modifications.
- Fail: This means your system has one or more leaks or structural defects. Further investigation usually with CCTV equipment is recommended to locate the issue.
- Inconclusive: Sometimes external factors such as trapped air, blockages, or environmental conditions affect readings. A retest or alternative method may be advised.
At London Drainage Services, we ensure all our reports are written in plain English, avoiding unnecessary jargon. You’ll receive a clear explanation of what was tested, the outcome, and what steps to take next.
Why Failing a Test Isn’t the End of the World
A failed drainage test doesn’t mean disaster it simply indicates the system needs attention. Leaks and cracks are common, especially in older London homes where clay or pitch-fibre pipes were often used.
Our experienced engineers will pinpoint the issue and recommend the most effective fix, such as drain repairs, relining, or replacing sections of damaged pipe. Once repaired, we retest the system to confirm it’s fully watertight and compliant.
This proactive approach saves homeowners from potential flooding, water damage, or costly emergency repairs later on.
When Drainage Testing Is Required
You might need a drainage test in several situations:
- During new drainage installation to certify system performance before completion.
- Before buying or selling a property to assess the drainage condition.
- When experiencing recurring blockages or damp patches.
- After major groundwork, construction, or landscaping work.
- When required by Building Control to verify compliance.
Our CCTV drainage surveys and pre-planned maintenance services help you stay one step ahead, ensuring your system continues to function efficiently year-round.
Compliance and Building Control
In London and across the UK, drainage testing must meet strict building regulations. Tests are often witnessed or approved by Building Control Officers to ensure systems are properly installed and sealed. This ensures public health standards are met and that wastewater doesn’t contaminate surrounding soil or water sources.
At London Drainage Services, all our testing and reporting procedures follow national standards, including the guidance set out by the Building Regulations Part H and BS EN 1610 for drain testing. Our team provides full documentation suitable for Building Control submissions, saving you time and hassle during inspections.
Why Choose London Drainage Services?
For over 20 years, London Drainage Services has been the trusted name in drainage solutions across London and the Home Counties. Our reputation is built on professionalism, transparency, and exceptional service.
We combine advanced technology with hands-on expertise to deliver accurate, reliable drainage testing and repair solutions. From initial inspection to final approval, we handle every step with care and precision.
Our approach is simple; no fuss, just fast, effective results that give homeowners peace of mind.
Book Your Drainage Test Today
If you suspect a problem with your drainage system or need a professional inspection for a new build or renovation, we’re here to help. Contact London Drainage Services today to book your comprehensive drainage testing service.
Our expert engineers will provide accurate results, clear explanations, and long-term solutions ensuring your home remains protected, compliant, and worry-free.