Drain Relining vs Excavation Cost | Which Is Cheaper

A cracked or collapsed drain leaves you with two options: reline it from inside without touching the ground, or dig down, cut out the bad section, and replace it. Both are legitimate. Both have a place. The problem is that plenty of homeowners, and some drainage contractors, default to digging because it's familiar, even when a liner would do the job better and cost less.

I've been doing no-dig relining for years. I'm not going to pretend it's always the answer, because it isn't. But I will tell you when it is, what each approach actually costs in the Horsham area, and what happens to both price tags when the job gets complicated.

What you're actually paying for in each method

Before the numbers, it's worth being clear on what each job involves, because the cost breakdown only makes sense if you know what you're buying.

Drain relining means inserting a resin-saturated felt tube into the existing pipe, inflating it against the pipe wall, and curing it in place, usually with hot water or ambient cure. The result is a smooth, jointless sleeve bonded to the inside of your old pipe. You don't touch the ground. A CCTV survey goes in first, often a second camera check follows the cure to confirm it's clean. The pipe effectively becomes a pipe within a pipe, and the new inner surface is what carries the flow from then on.

Excavation and replacement means a digger breaks open the ground above the damaged section, the old pipe is cut out, new pipe is laid, joints are made, and the ground is reinstated. If it's under a driveway, patio, or garden, those surfaces get broken up and, budget permitting, put back.

The labour in a reline is mostly skilled, camera-led, technical work. The labour in a dig is mostly physical: machinery time, spoil removal, concrete cutting if needed, and surface reinstatement. That difference drives the cost more than almost anything else.

The honest cost ranges

These are real ranges for domestic and small commercial jobs in Horsham and the surrounding RH12 and RH13 postcodes. Not quotes, not guarantees, just what I see in practice.

A couple of things to note. The reline price gap over a plain open-garden dig is relatively narrow, sometimes relining costs more on a simple accessible job. The gap blows open the moment you add a hard surface, a deep pipe, a narrow access point, or a tight urban plot. That's when no-dig earns its name.

The survey cost applies to both. Anyone quoting without one is guessing.

What drives each price up

For relining

The single biggest factor is pipe diameter. A 100mm foul drain is the common domestic size, and liner costs reflect it. Step up to 150mm, 225mm, or larger on a commercial site in Broadbridge Heath or Billingshurst, and the resin and felt materials scale up fast.

Pipe condition matters too. A pipe that's cracked and deformed but roughly circular can be lined without drama. One that's collapsed to less than about 75% of its original bore may not take a liner at all, or may need grinding and root-cutting first to create a workable surface. That pre-work adds cost and time.

Access is the other variable. Two manholes close together, easy camera access, good working space, the job moves quickly. One manhole, a long run, a 45-degree bend partway through, that's slower, and slower means more on the invoice.

For excavation

Surface type is the killer. Digging through a lawn is cheap, relatively speaking. Digging through a concrete driveway on a Roffey terrace or a block-paved front garden in Littlehaven is a different proposition entirely. Diamond cutting, spoil removal, skip hire, and then reinstating the surface to something like its original state, those costs stack up and they're not small numbers.

Depth is the other one. Most domestic drains in Horsham sit 600mm to 1.2 metres down. But older properties, particularly in Denne or around the town centre, sometimes have much deeper runs, and deeper means more spoil, more shoring risk, longer labour. A pipe at 2.5 metres is not the same job as one at 0.8 metres, even if the pipe length is identical.

Relevant utilities add time and therefore cost. Hit a BT duct or a water main, and you're dealing with notifiable works.

When relining is genuinely the right call

A pipe under a driveway with root ingress and hairline cracks. A 6-metre run under a landscaped garden that a homeowner in Southwater has just had returfed. A Victorian drain in Warnham with original earthenware joints that are letting in fine root fibres. A pipe serving a rental property in Tower Hill where the tenant can't be without drainage for three days while a dig crew reinstates the surface.

In all of those situations, relining wins unless the pipe is structurally beyond repair. It's less disruptive, faster, and almost always cheaper once you factor in surface reinstatement. The liner we install carries a 20-year guarantee on the remedial work, so you're not left wondering how long it'll last.

Relining also works on bends, which surprises some people. Flexible liner technology handles reasonable changes in direction. It won't navigate a 90-degree knuckle bend, but a standard 45 or a swept junction isn't a problem.

When excavation is the right call

Some pipes are beyond relining. A section that's fully collapsed, crushed flat by vehicle loading, or offset so badly that a camera can't even pass through it, you can't line what isn't there. You need to dig, replace, and compact properly.

Joint displacement on older clay pipe runs is another case. If the pipe has dropped significantly, relining it creates a smooth inner surface but doesn't fix the underlying fall. Water flows by gravity. A pipe with a back-fall or a belly will still pond even after lining. The CCTV survey should tell you this, and if it does, you're probably digging.

There's also a cost inversion on very short, very accessible sections. If you've got 1.5 metres of pipe that's snapped cleanly at a single joint, it's exposed in an open garden with no surface to reinstate, and a replacement pipe length and two rubber couplings will sort it, a full liner might be over-engineering the fix.

And sometimes a homeowner's insurance explicitly requires replacement with new pipe, not lining. Check your policy wording before you commit.

Why the survey isn't optional

Every week I see jobs quoted (by others, and occasionally by homeowners who've been told by a well-meaning neighbour) without a camera in the drain. You can't know which method is appropriate until you've seen the pipe condition, the location of the damage, the depth, the pipe material, and the bore.

A CCTV survey for a typical domestic drain in Horsham costs £150 to £350. Set against a repair bill of several thousand pounds, that's not a lot to ask. It also protects you: a proper survey gives you a written defect report, which you can use to get two or three quotes from different contractors on a like-for-like basis.

We run CCTV surveys across the Horsham area, from Pulborough and Cowfold in the south to Rudgwick and Slinfold in the north, and the report we provide will tell you exactly what's there, not what we'd prefer to find.

The real-world maths, summed up

For a cracked drain under a typical Horsham driveway, relining will usually come in at roughly half the total cost of excavation once you price in the concrete cutting and surface reinstatement. For a pipe lying in open garden soil with a single clean break, the gap narrows and excavation might be the simpler call. For anything longer than 3 metres, under any hard surface, or on a property where access is tight, no-dig wins almost every time.

The 20-year guarantee on our remedial work applies equally to lining and to pipe replacement, so longevity isn't a reason to choose one over the other. Both, done properly, should outlast the problem.

If you've had a quote to dig up your driveway in Holbrook, Trafalgar, or North Heath and something about it doesn't feel right, get the camera in first. It might not change the answer. It might change it completely.

Drainsco covers Horsham and the RH postcodes, with engineers available 24/7. There's no call-out fee, and we'll give you a clear price before anyone touches anything. Call us or book a CCTV survey online and we'll tell you exactly what you're dealing with.