Three main sewer replacement methods are available, each with advantages and drawbacks.
The main methods are:
- Fully Excavated Replacement
- Trenchless Excavation (Pipe Bursting)
- Epoxy Lining
Fully Excavated Replacement
The fully excavated replacement method is as it sounds: the sewer is dug up and replaced. When done correctly, physical removal and replacement is the leading method for a perfect new sewer. You may be surprised how this method affects your sewer line replacement cost.
Due to its simplicity and lack of expensive technology, the excavation method is, on average, the least costly sewer line replacement method. However, if you have to repair landscaping or hardscaping as a result, it could be the costliest method for you.
What can drive the price up or down for a sewer excavation project?
-
- The depth of the sewer. Deeper sewer depths require more labor, equipment, heavier-duty machinery, and carry higher insurance liability. Any sewer over 7ft deep is a high-liability project, so the cost is driven down the shallower the sewer is. Sewer depths over 7ft can add thousands to your sewer project, and depths over 9ft can double the sewer line replacement cost.
- Obstacles to the sewer line. Obstacles are the most significant cost factor when excavating your sewer. Common excavation obstacles include concrete, streets, buried utilities, landscaping, fencing, home additions, and boulders. Fewer obstacles will drive the cost down. Significant obstacles can add $3,500 to $6,500 to a project, which makes a big difference in your sewer line replacement cost.
- Inaccurate sewer line location. Sewer estimation can be complex, and a plumber must do a sewer location service using a sewer video system that emits a location beacon while traveling down your sewer. The signal-receiving wand can give false signals if the sewer is deep and at a steep angle or if electrical interference from an electrical utility is nearby. Few things are worse for a sewer replacement project than digging deep to discover there is no sewer where the location equipment said there was. The good news is that a highly experienced plumber can read the warning signs before the project begins. Accurate sewer location doesn’t drive the cost down on the front end, but it does keep it from driving up mid-project, which keeps your sewer line replacement cost down.
- Landscaping and Hardscaping. Sewer excavation requires things that are in the way removed and ideally put back. Plumbing companies are not the ideal contractor type to do this work since it is not their specialty. Some companies may include this in their bid but are likely subcontracting the work, which means you will pay a premium. Most plumbing companies only include soil backfill and basic concrete flatwork in their proposals so that you can choose your landscaping contractors, which should drive your sewer line replacement cost down.
Trenchless Excavation (Pipe Bursting)
Trenchless excavation involves digging a hole at the beginning of the sewer and another at the end. The remaining piping in between is replaced underground without digging a trench. A machine pulls a new sewer pipe through the existing underground sewer piping. Since the new sewer piping is the same size as the old sewer, a unique spear-like head breaks the old sewer apart when pulled through. This breaking away of the old piping is often called “pipe bursting.”
Suppose you have obstacles to trenched excavation and a good drainage slope the entire distance of your sewer. In that case, trenchless excavation is likely the option with the lowest sewer line replacement cost.
What can drive the price up or down for a trenchless excavation project?
- Obstacles. Though there is no trenching, there is still a considerable amount of excavation required to expose each end of the sewer with enough room for plumbers to work, fit the hydraulic bursting equipment, and feed the new seamless sewer piping through. The same obstacles that drive the price up for complete excavation projects also apply to trenchless excavation, but the advantage here is that they are less likely to be encountered, which drives the sewer line replacement cost down.
- Pipe Bursting Equipment. The technological equipment used is costly, with complete systems retailing more than $100,000 for the plumbing contractor. While this may save some labor and landscaping, clients pay for the equipment use, which drives the plumbing portion of the project price upward. But the lack of excess landscaping needed after the project is completed drives the total sewer replacement cost back down.
- Inaccurate sewer location. Sewer estimation with the trenchless excavation method is just as complex as a fully excavated project. A plumber must still do a sewer location service using a sewer video system that emits a location beacon while traveling down your sewer. The same pitfalls apply here as well. Remember that accurate sewer location doesn’t drive the sewer line replacement cost down on the front end but keeps it from driving up mid-project.
- Landscaping and Hardscaping. Since there is no trenching, you only have to worry about the backfilled holes at each end of your sewer, making this why the trenchless method of replacing sewers is popular. The lack of excess landscaping repair drives the total sewer line replacement cost down.
Epoxy Lining
Epoxy lining involves soaking a long felt sleeve in epoxy, shooting it down your sewer with pressurized equipment, and then curing it dry. Where branch lines attach, robotic equipment is sent down the piping to cut holes in the cured epoxy sleeve to allow drainage connections to function normally. Excavation on one end of the sewer is still required so that the equipment can shoot epoxy-soaked felt liners directly into the sewer.
Though it is the least destructive method, it has, on average, the highest sewer line replacement cost. This method is appropriate when landscaping or other obstacles financially complicate the other sewer replacement options.
What can drive the price up or down for an epoxy lining project?
- Epoxy Lining System Equipment. The technological equipment used is costly, with complete epoxy lining systems retailing more than $150,000 for the plumbing contractor. While this may save some labor and landscaping, clients pay for the equipment use, which drives the plumbing portion of the sewer line replacement cost upward. The lack of excess excavation needed helps justify the premium cost.
- Pipe Size. The size of the piping determines the amount of materials used and dramatically affects the project’s cost. 4” epoxy liner costs average around $170 per foot, while 6” liners average about $225 per foot for the piping alone.
- Pipe Preparation. To ensure the epoxy sleeve fits through your whole sewer pipe in an optimal circular shape, it must have removed all of the debris inside of it. Debris would include scum and grease build-up and root intrusions regarding clay ceramic sewer piping. Depending on the level of waste and roots in the sewer, this can be labor-intensive and significantly impact your sewer line replacement cost. This process involves high-pressure hydro-jetting equipment. Removing the debris in a ceramic clay sewer to prep the piping can cost between $750-$1500 on average.
If your sewer is cast iron or a portion of it, the plumber must descale the sewer of years of rust and mineral build-up. This process involves a machine that inserts a cable into the sewer and spins a head of abrasive chains at high speed to remove the scale. Cast iron pipe descaling is a labor-intensive process that can cost $3,500-$5,500 on average. This cost includes using the descaling chain system and the high-pressure hydro-jetter to wash all the removed scale down the sewer.
- Reinstatements. Reinstatements are rare but can significantly impact your sewer line replacement cost. Pipes that connect to your sewer get blocked off after the installation of the epoxy liner sleeve down the main sewer piping, and the connections must be re-opened for flow to continue. Robotic equipment enters the sewer liner and cuts openings where the connections are, thus reinstating that connection. The first reinstatement typically costs between $1,500 and $2,500, with additional reinstatements costing $750 each on average.
- Indoor/Outdoor Access. The plumbers must excavate at least one end of the sewer to gain the direct access required to inject the epoxy liner. If you have an unfinished basement, excavating inside the basement is ideal since the hole may be less than five cubic feet. If you have a finished basement or the equipment does not fit in your home, a large hole may need to be excavated outside the house to gain proper access. A deep outdoor excavation would drive up your sewer line replacement cost and could add $3,500 to $6,500 to your project.
- Obstacles. If your situation requires outdoor excavation, all of the obstacle risks associated with the alternative sewer replacement methods will also apply to your epoxy lining project.