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Trenchless Sewer Repair and Replacement

John is an experienced freelance content writer with an eclectic employment history and enjoys sharing his home improvement knowledge.

Nobody relishes the idea of problems with their drains and sewers. A blocked drain can cause backed-up pipes and unpleasant odours on your property, but cracked and broken sewer pipes can cause severe damage to the surrounding land.

Unfortunately, getting to a sewer pipe is no small task. We bury our sewer pipes underground for a good reason, but it means we have to dig them back up again to repair or replace them. Sewer pipes often travel under our gardens and driveways. In short, in areas that we don't want to dig up. Luckily, there are a few options.

Trenchless sewer repair has been a revelation in the plumbing world, allowing technicians to repair underground sewer pipes without the disruptive process of digging them up. This technique uses a variety of methods (anything from blockages to cracks and breakages and even tree root ingress) that allow sewers to be handled without lifting so much as a sod of dirt.

Types of Trenchless Sewer Repair

An experienced technician will always choose the right tool for the job, and there is more than one way to carry out a trenchless sewer repair.

Slip Lining

As new as trenchless sewer repair may feel, slip lining is a method of repairing sewer pipes that is nearly a century old! This method involves inserting a smaller diameter pipe into the damaged pipe. The cavity between the pipes is then filled with grout. This not only creates a new, sealed pipe on the inside, but it also greatly strengthens the pipe; as the pipe wall now consists of the new pipe wall, the old pipe wall, and the filler grout.

While this is technically a trenchless technique, it is worth noting that it is more invasive than the other methods we are going to mention. A pit will likely need to be dug in order to get the new pipe section in place.

Spray Lining or Brush Coating

Spray lining involves spraying or brushing a coat of flexible polymer onto the inside surface of the damaged pipe. This coat will then set, sealing any cracks and strengthening the outer wall of the pipe.

Cured In Place Pipe (CIPP) Lining

Also known as structural pipelining, this technique involves sliding a lining into the damaged pipe. The lining is then inflated, causing it to expand to fill the inner diameter. It is then left to cure.

The resulting lining seals off any cracks—and even small holes—and can also leave the repaired pipe more structurally sound than it was when it was new!

Pipe Bursting

Pipe bursting is precisely what it sounds like. This technique involves inserting a new pipe that is the same or a similar diameter to the old one. The new pipe has a "bursting head" fitted at the leading end, and as it is pushed through, it bursts the old pipe to make space for the new one.

Why Choose Trenchless Sewer Repair?

There are many benefits to trenchless sewer repair over other methods. The main one we have already touched on is less disruption. You don't need to worry about your garden or driveway getting turned into an excavation site. On a similar note, it is generally a much faster process, meaning what little disruption there is with trenchless sewer repair won't go on for as long.

It is also considerably more cost-effective. It may seem expensive when you compare the cost of the repair alone, but when you factor in the additional costs and time involved in having large parts of your property dug up, the price of trenchless sewer repairs starts to look a lot more attractive.

Trenchless sewer replacements are not a quick fix, either. Some trenchless repairs are rated to last as much as 50 or even 100 years!

Multiple Drains Backing Up

A backed-up drain is a surefire sign of a problem, but if it is just one sink or one toilet, the chances are it is just that sink or toilet's drain that is having problems. Granted, that's still an issue, and one you'll probably need to get an expert out to fix, but it's perhaps not a sewer problem.

If, on the other hand, you have drains backing up in multiple places, or even all the drains in the property, that would point to a significant sewer blockage.

Also, be on the lookout for large plants and trees growing along the path of your sewer pipes. Root ingress is one of the more common causes of sewer blockages and happens when the roots of plants—most commonly trees—find their way into your pipes and expand, filling the inner space and blocking the sewer.

Blocked sewers can cause your drains to backup. Individual drains are more likely to be a localised problem, but widespread backing up indicates a more significant blockage further down the line.

Blocked sewers can cause your drains to backup. Individual drains are more likely to be a localised problem, but widespread backing up indicates a more significant blockage further down the line.

Swampy Ground

Over the long years that a sewer pipe is in use, it will naturally deteriorate. The process can be exacerbated by things like movement in the surrounding land, root ingress and, ultimately, the pipes can crack and break. When this happens, the sewage in those pipes leaks out into the surrounding ground and can cause it to become swampy in particularly bad cases. You may also notice more plant growth in those areas as plants feed off of the nutrients in what is essentially fertiliser.

Unpleasant Odours

Like drain blockages, problems in your sewer can cause unpleasant odours to linger around the property. These odours should not come from your indoor plumbing—unless there are issues with the plumbing itself—but there are always places where noxious gases will escape if they are allowed to build up in your sewer pipe.

Blocked sewers shouldn't cause unpleasant odours to come from your sinks and toilets, but there are other places they could escape.

Blocked sewers shouldn't cause unpleasant odours to come from your sinks and toilets, but there are other places they could escape.

Preventative Measures

Beyond general good practice and common sense—don't pour fat down the sink, don't flush things you shouldn't flush, that kind of thing—it is good practice to have your drains inspected every so often. For an average home, two years is generally considered to be a good interval for sewer inspection. If you are dealing with a larger than average home, or a commercial property, it would probably be best to make that every year.

Sewer inspections may feel like an inconvenience and unnecessary expense, but they will typically save you money in the long run. Repairing a sewer problem that has been left to escalate will invariably be more expensive and time-consuming than catching a problem early and dealing with it then.


Repairing a broken sewer does not mean the disruptive excavation process it once did. Trenchless sewer repair offers a variety of methods for dealing with sewer issues without the major upheaval of the surrounding area, from leaks and blockages to complete pipe replacements.

When it comes to those problems, keep an eye out for the warning signs, but don't fall into the trap of feeling like you should only get your drains inspected when you believe there is a problem. Doing so could result in far more inconvenience and expense in putting the problem right. And nobody wants that.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2020 John Bullock