What to Do After a Drain Survey Report: Next Steps

You have received your drain survey report. You have seen the images of the pipes, read through the findings, and now you are wondering: what does this mean, and what do I need to do about it? This guide walks you through interpreting the report, understanding what needs attention, deciding between repair options, and getting the work done.

Understanding the Defect Grades

The most important part of any drain survey report is the condition grading system. This standardised system tells you how urgent each defect is and when — if at all — you need to act.

The industry standard is the WRc (Water Research Centre) system, which uses five grades:

Grade 1 — Acceptable Condition

The pipe is in good working order. Minor cosmetic defects may be present — slight discolouration, minor deposits on the inside — but nothing that affects structural integrity or flow. No action is required. If you have received a report with only Grade 1 findings, your drainage system is in good condition. You can relax.

Grade 2 — Minor Defects

The pipe has defects that do not currently affect function but should be monitored. Examples include hairline cracks that are not leaking, slight joint displacement (less than 10% of the pipe diameter), and minor root ingress that is not obstructing flow.

Grade 2 findings are not urgent, but they are not something to ignore. The recommendation is usually to re-inspect the affected section in 2–5 years to ensure the defect is not progressing. If it is progressing faster than expected, repair it sooner. If it is stable, you can wait.

A practical example: a Grade 2 crack in a modern PVC pipe might remain unchanged for 20 years. A Grade 2 crack in a 100-year-old clay pipe might progress to Grade 3 within 3–5 years. The material and the specific defect determine the urgency.

Grade 3 — Defects Requiring Attention

The pipe has defects that will likely worsen over time and should be repaired within 12 months. Examples include moderate joint displacement, established root ingress causing partial obstruction of flow, and moderate scale or debris buildup.

A Grade 3 defect is a “plan the repair” situation, not an emergency. You should contact drainage contractors for quotes, understand your repair options, and schedule the work at a time that is convenient for you. But do not leave it much longer than a year — waiting allows the defect to progress to Grade 4.

Grade 4 — Significant Defects

The pipe has serious defects that are actively affecting function and will continue to deteriorate. Examples include severe joint displacement, dense root masses blocking most of the pipe, partial collapse, and heavy deformation of pitch fibre pipes.

Grade 4 findings require action within the next few months. They are not immediately life-threatening (you are not going to wake up flooded tomorrow), but they are getting close. Your drainage system is actively deteriorating, and delays increase the risk of a complete failure.

Grade 5 — Urgent or Collapsed

The pipe has failed or is about to fail. Full collapse, complete obstruction, or structural failure that poses a real risk of flooding or sewage backup into the property.

Grade 5 is urgent. Contact contractors immediately and get emergency quotes. This is the point where delays result in actual property damage. If you are not careful, you will wake up to a flooded basement or sewage backing up into your kitchen.

Common Defects and What They Mean

The report will list defects using standardised terminology. Here is what the most common ones mean and what each requires:

Root Ingress

Roots from nearby trees have entered the pipe through joints or cracks. If minor and not obstructing flow, it may be Grade 2. If roots are densely packed and restricting flow, it is Grade 3 or higher.

Root ingress is particularly common in Manchester suburbs like Didsbury, Chorlton, and Withington, where properties have mature gardens with large trees. Willows, ashes, and sycamores cause most damage.

Options: Root cutting (temporary, the roots will return), or re-lining (a permanent solution). If the tree is causing repeated damage, it may be worth removing or relocating the tree — though this is an extreme solution that most homeowners prefer to avoid.

Displaced Joints

The pipe sections have shifted slightly out of alignment at a joint. Measured as a percentage of the pipe diameter — a 10% displacement is barely noticeable; a 50% displacement is severe.

Small displacement (Grade 2) may be stable and cause no problems. Larger displacement (Grade 3 or higher) traps debris and allows root ingress, so it should be repaired.

Options: Excavation and relaying the affected section(s), or patch repair if only one joint is affected.

Fractured Pipes

A crack running around the circumference (circumferential fracture) or along the length (longitudinal fracture) of the pipe.

Small hairline cracks may not leak (Grade 2). Wider cracks with visible water penetration (Grade 3 or higher) need attention.

Options: For isolated cracks, patch repair or re-lining. For multiple fractures indicating structural stress, full excavation and replacement may be necessary.

Deformation

The pipe has changed shape — common in pitch fibre pipes from the 1950s–1980s, which soften and collapse over time.

Early deformation (Grade 2 or 3) reducing the bore by 25–40% may not cause immediate blockages, but it will worsen. Advanced deformation (Grade 4 or 5) is actively restricting flow.

Options: Re-lining (structural lining that restores the bore of the pipe) or full replacement.

Collapse

The pipe has caved in, partially or completely blocking flow.

Options: Excavation and replacement. This is the most expensive option but sometimes necessary.

Repair Methods and Their Costs

Once you know what the defects are, the next step is understanding your repair options. Different defects have different solutions, and costs vary significantly.

Patch Repair

For isolated defects affecting a short length of pipe (e.g., one cracked section or displaced joint), a patch repair is often sufficient.

The contractor excavates around the affected area (typically a 1–1.5m section) and removes the damaged pipe. New pipe is installed, joints are sealed, and the ground is made good. The pipes are then re-tested with water to confirm the repair is successful.

Cost: £800–£1,500 for a single defect. Multiple defects in different locations require multiple excavations, which can add up.

Advantages: Targeted, often less disruptive than a full re-line, removes the problem entirely.

Disadvantages: If the rest of the system has similar defects, you are only fixing one section. Future repairs may be needed elsewhere.

Excavation and Full Replacement

If defects are extensive or scattered along a long length of pipe, full replacement of the affected section may be more cost-effective than multiple patch repairs.

The contractor excavates along the entire defective run, removes the old pipe, installs new pipe with proper bedding and compaction, and makes good the ground. Any external structures (paths, patios, driveways) above the pipe are removed before excavation and reinstated afterwards.

Cost: £1,500–£5,000 for a straightforward run, higher if depth is significant, excavation is difficult, or external structures need to be removed and reinstated.

Advantages: Fixes the entire section, prevents future problems in that area.

Disadvantages: Disruptive if it means breaking up patio or driveway, time-consuming, more expensive upfront than a patch repair.

Re-lining (CIPP — Cured In Place Pipe)

For pipes with multiple defects, internal deterioration, or deformation (particularly pitch fibre), re-lining is often the modern solution.

A flexible liner impregnated with epoxy resin is inverted into the damaged pipe, or is pulled through it. Once in place, it is cured (hardened) by either hot water, steam, or UV light, creating a new structural pipe inside the old one. The lining restores the internal surface, stabilises defective joints, and restores the bore of deformed pipes.

Cost: £1,500–£4,000 for a 25–40m run, depending on pipe diameter and access.

Advantages: Non-invasive (no excavation needed), quick (a day or two per run), and very durable (30+ year lifespan).

Disadvantages: Cannot be used if the pipe has collapsed completely or is already fully blocked. Slightly reduces the internal diameter of the pipe (though this is rarely a practical issue). Not all defects can be treated this way.

Root Cutting and Descaling

For pipes blocked by roots or scale, a mechanical root cutting or descaling service clears the blockage.

A rotating cutting head or flail is fed into the pipe and removes the obstruction. This is temporary — the roots will regrow unless the crack they entered through is sealed.

Cost: £150–£350 per blockage.

Advantages: Cheap, quick, restores function immediately.

Disadvantages: Temporary solution. If root ingress is Grade 3 or higher, it will block again within months or a year. Considered a holding action, not a proper repair.

Deciding When and How to Repair

Use the condition grades in your report as a guide:

Grade 1 or 2 findings: No urgent action needed. Arrange a re-survey in 3–5 years to check for progression. Monitor the affected area (e.g., watch for recurring blockages) in the meantime.

Grade 3 findings: Plan a repair within the next 12 months. Get quotes from 2–3 contractors, compare their proposed methods and costs, and schedule the work at a time convenient for you. Do not rush, but do not delay beyond 12 months.

Grade 4 findings: Contact contractors within the next month. Aim to have work completed within 3–6 months. This is not a panic situation, but it is serious and should not be ignored.

Grade 5 findings: Contact contractors immediately. This is an emergency or near-emergency. Get quotes and aim for completion within 2–3 months or sooner.

Obtaining Repair Quotes

Once you know what needs to be repaired, contact drainage contractors (not general plumbers — you want specialists with experience in pipe repair, not just blockage clearing).

Provide the contractor with:

1. A copy of your drain survey report (or at minimum, the key details and images).
2. A description of what you want repaired.
3. Access details and any site-specific information (e.g., “the affected section runs under the patio” or “it is in the back garden next to a fence”).

The contractor will assess the job and provide a quote. Get at least two quotes — costs vary based on the contractor’s experience, the specific method they propose, and site-specific factors.

Do not automatically choose the cheapest quote. Ask what method they are proposing and why. A contractor proposing re-lining for a single crack may be overcomplicating it. A contractor proposing multiple patch repairs when re-lining would be simpler may be inefficient. Understand the difference and ask questions.

Your Responsibilities During Repair

When repairs are carried out, you need to:

1. Provide access — ensure the contractor can reach the affected area safely.
2. Arrange for any ground breaking to be done at a time that suits you — for example, if the repair involves breaking up your patio, plan for the inconvenience.
3. Arrange for re-instatement — clarify whether the contractor is responsible for reinstating paths, patios, or driveways or whether you need to arrange this separately.
4. Get a completion certificate — once repairs are done, ask for a written completion certificate or report confirming that the work has been carried out satisfactorily and in compliance with Building Regulations if required.

After the Repair — Re-Testing and Certification

Once repairs are complete, the contractor should re-test the repaired section using water under pressure. This proves that the repair is successful and that joints are properly sealed.

Ask for a pressure test certificate and, if the repairs involved Building Regulation approval, a completion certificate from Building Control.

These certificates are useful if you ever sell the property — they provide evidence that the drains were professionally repaired and tested.

Claiming on Insurance

If your drain failure is covered by home insurance (subsidence, escape of water, or damage caused by flooding), you may be able to claim the repair cost. However, insurers often require:

1. A professional drain survey report (you now have this).
2. Quotations from the contractor.
3. Proof that the work was carried out (receipts, completion certificates).

Provide your insurer with the survey report and quotes before committing to the repair — they may have preferred contractors or require approval of the proposed method.

The Bottom Line

A drain survey report gives you the information you need to make decisions about repairs. Use the condition grades to decide urgency, understand your repair options (patch, full replacement, or re-lining), get competitive quotes, and plan the work at a time that suits you.

Do not panic at a Grade 3 or Grade 4 finding — these are common, fixable, and manageable. Do address them within the recommended timescale. Ignoring Grade 4 and Grade 5 findings will result in more expensive emergency repairs later.

If you have received a drain survey report and are unsure about the next steps, or want advice on repair options, get in touch. We can walk you through the findings and help you understand your options.