Jetting vs excavation: decision tree
After a CCTV survey, the next decision is usually not “dig or don’t dig” — it is whether soft cleaning will restore flow, whether a no-dig repair can fix a local defect, or whether excavation is the honest fix. This guide walks UK homeowners and buyers through that tree using camera findings, not sales pressure.
What you’ll learn
- A step-by-step decision path from blockage type to treatment
- When jetting is enough — and when it can make a collapse worse
- Where lining and patch repairs sit between clean and dig
- Planning cost bands and questions to ask before you approve work
Start here: what did the camera show?
Use the written report and footage, not a verbal summary. If distances and stills are missing, fix the report first — see what a good drain survey report includes.
| Finding (plain English) | Usually try first | Escalate when… |
|---|---|---|
| Grease, silt, soft debris, wet wipes mass | High-pressure jetting (± descaling) | Same blockage returns within weeks, or pipe wall is damaged |
| Roots at joints; pipe still round | Root cut + jet; then monitor | Roots return often, or joint displacement is structural |
| Local crack / fracture; line still holds shape | Patch, short liner, or point repair | Multiple defects, ovality, or lining cannot seal the joint |
| Deformation, severe displacement, missing invert | Engineered repair plan — often dig or full liner | Access, depth, or shared ownership blocks lining |
| Collapse, open void, camera cannot pass | Excavation / replacement (planned) | Emergency flooding — temporary overpump may come first |
Decision tree (follow in order)
- Is the line flooded or completely impassable? Clear enough water or debris for a useful CCTV pass if safe. Do not approve major digs from a “blocked — can’t see” note alone if access can be improved.
- Is the obstruction soft (grease, silt, paper, fat)? Yes → jet (and often re-CCTV). No → skip to structural checks.
- Are roots present with an intact pipe profile? Yes → cut/clean, document joints, set a monitor interval. Repeated invasion → liner or joint repair.
- Is there a localised structural defect with enough remaining integrity? Yes → ask about patch / CIPP liner / point repair quotes with before/after CCTV. No → excavation or longer replacement.
- Is there collapse, severe ovality, or missing pipe? Plan excavation (or full replacement of that run). Aggressive jetting into a known collapse can enlarge voids and undermine slabs or gardens.
- Is ownership private vs water-company clear? If unsure, pause paid structural work until the boundary is checked — digging the wrong asset wastes money and can create liability.
When jetting is the right first move
- Slow baths or toilets with no outdoor flooding and a history of grease or “flushable” wipes
- Camera shows soft debris and an otherwise sound clay, plastic, or concrete wall
- You need flow restored urgently and structural work can wait for a second quote
- Insurance or a landlord asks for proof of clearing before approving repair
Ask for a short re-CCTV after jetting when you paid for a condition survey. Cleaning can hide cracks that silt was masking — or confirm the pipe is fine so you stop at maintenance.
When excavation (or major dig) is the honest answer
- Collapse, large open joints with soil ingress, or pipe sections missing
- Severe deformation so a liner cannot form a reliable seal
- Repeated failures at the same chainage after clean + monitor
- Pitch-fibre or other failed materials where lining quotes are speculative without a solid host pipe
- Need to reset falls, replace a broken chamber, or rebuild a shared junction under a driveway (plan traffic and reinstatement costs)
Excavation quotes should name depth, surface type (lawn vs block paving vs tarmac), spoil removal, and reinstatement — not just “dig and replace pipe.”
The middle path: lining and patch repairs
No-dig options sit between jetting and open excavation when the host pipe can still support a liner or patch:
- Spot / patch repair — short structural defect with good upstream and downstream pipe
- CIPP / cured-in-place liner — longer defective run where diameter and access allow
- Robotic cut + seal — after lining, reinstate laterals carefully
Good lining quotes include pre-clean, pre- and post-CCTV, curing method, and warranty terms in writing. Be wary of lining sold as a cure-all for collapses the camera never fully mapped.
Planning cost bands (UK estimates)
Figures are planning ranges for domestic laterals — not quotes. London and hard surfaces often sit higher; rural long runs vary. Confirm VAT and reinstatement.
| Work | Often around | Notes |
|---|---|---|
| Jetting (single domestic visit) | £80–£250+ | Often priced with or after CCTV; complex grease may need longer |
| Root cut + clean | £150–£400+ | Does not stop roots returning through open joints |
| Patch / short liner | £400–£1,500+ | Depends on diameter, access, and defect length |
| Longer CIPP liner | £1,000–£several thousand | Meterage, laterals, and curing drive price |
| Excavate & replace short run | £800–£3,000+ | Depth and surface reinstatement dominate |
| Deep dig / driveway / shared junction | £2,000–£10,000+ | Get two written scopes; check who owns the asset |
For survey-only pricing, see CCTV drain survey cost UK.
Questions to ask before you approve work
- Which exact metres of pipe are you treating, from which chamber?
- Is this operational (flow) or structural — and what happens if we only jet first?
- Will I get post-work CCTV and stills?
- What is included for spoil, traffic management, and surface reinstatement?
- Is this run private, shared, or water-company — and have you stated uncertainty in writing?
- What warranty covers lining or new pipe, and what voids it?
Buyers: use the tree before you renegotiate
Pre-purchase CCTV often lands mid-survey window. Map findings to this tree before you demand a price reduction:
- Soft clean only → usually a maintenance negotiate, not a structural one
- Liner or patch → get a second quote with the seller’s report attached
- Collapse / dig → retention, price chip, or walk-away depending on scale and solicitor advice
Keep the footage pack. A second firm quoting from the same chainage is how you test whether excavation is necessary.
FAQ
Can jetting fix roots permanently?
Usually no. Cutting clears the bore; roots often return through open joints. Permanent fixes address the joint (liner, seal, or replacement) plus any nearby trees as a separate landscaping decision.
Should I jet before every CCTV survey?
Not always. A dirty line can hide defects, but a clean-first approach can also flush evidence of soft blockages. Many firms survey first, jet if needed, then re-CCTV for structural confirmation — ask which sequence they use and why.
Is lining always cheaper than digging?
Often for mid-length defects with good access. Deep, short collapses under a driveway can favour a targeted dig. Compare like-for-like scopes, including reinstatement.
Are listings on this site paid?
Featured or lead placements are labelled when used. We may earn a lead or referral fee if you request a quote from a listed engineer.
Related
- CCTV drain survey cost UK
- What a good drain survey report includes
- All DrainCam UK guides
- Browse local engineers
Disclosure: DrainCam UK may earn a lead or referral fee if you request a quote from a listed engineer. Cost bands are planning estimates only. This guide is general UK homeowner and buyer guidance, not a site-specific engineering or legal opinion on drain ownership or repair methods.