Today’s Cost to Replace a Cast Iron Drain Under Your Home

By |Published On: January 1st, 2021|Categories: Residential Plumbing, Sewer Systems|

Signs that you need to replace a cast iron drain pipe

Most homes built before the 1970s were made with cast iron drain pipes. They were designed to last 50 to 100 years, but because of unavoidable circumstances, their lifespans can be cut short. Things like weather, tree roots, types of soil, and water quality will affect their structural integrity.

Read also: How To Find The Main Sewer Line In the House

Cost to Replace a Cast Iron Drain

There are many pros to cast iron sewer pipes, like their strength and sound deadening abilities. But cast iron still fails. Here are the signs you may notice that signal the pipes are failing or have failed. 

  • Leaks – Corrosive materials, like drain cleaner and sulfuric acid, can damage the pipes leading to cracks. A simple CCTV sewer camera inspection can find the exact location of the crack. 
  • Odor – Because sewer lines are filled with waste, if the pipe is failing, you will probably be able to smell foul odors like rotten eggs and sewage. Breathing in these fumes over time can lead to even larger health concerns. 
  • Backups – Slow draining and clogs can be a sign your pipes are failing. Even cleaning products contain sulfuric acid which is damaging to cast iron pipes. 
  • Mold – Mold can begin to grow due to increased humidity in your home. A cracked pipe will heat your home and create the right mold growth conditions. 
  • Signs in your lawn – Leaking sewage acts as a fertilizer and your grass can show signs of extreme growth or a lush green color. If you notice puddles of water or sewage waste in your yard, you can be certain a pipe is cracked and leaking. Your soil can sink, develop strange bumps, or even gutters due to soil dissipating. 
  • Foundation Cracks – Leaking pipes can disrupt your foundation and cause walls, floors, or ceilings to crack. Call a foundation repair specialist if the situation gets this bad.
  • Infestations – Rodents and insects (cockroaches, palmetto bugs, and flies) can find their way through even the tiniest of cracks, and make their way into your home. Pest control can kill the current invaders but more will come if the root of the problem is not handled. 

What’s the difference between REPAIRING a cast iron drain pipe, and REPLACING a cast iron drain pipe?

Repairing a cast iron drain pipe is very close to just being a temporary solution. It can involve just patching up sections of your leaking pipes, allowing other sections to fail, and leading you to just call the plumber again. Repair is like a band-aid solution to failing or failed pipes. 
Repairs are like “putting out fires” whereas the problems will come back, and you are not extending the lifespan of the pipes. 
Replacing a cast iron drain pipe is the most recommended route to a damaged cast iron pipe. There are two major paths for replacing a cast iron drain pipe. Dig up and replace involves, like the name suggests, digging long trenches to remove the old pipe and laying down the new pipe. The cleaner, cost-effective solution is called trenchless sewer repair. This method avoids digging long trenches and comes with a few sub-types. 
Replacement allows you to no longer depend on old, rusting, leaking and failing pipes. 

Cast iron drain pipe repair methods

  • Patch jobs – A patch job is a quick emergency repair fix, usually to stop a sudden leak. It’s not meant to be a permanent solution and most of the tools for a patch job can be picked up at the store. A few repair items include black repair wraps and epoxy adhesives. 
  • Point repairs –  Point repairs are like CIPP (cured-in-place pipe), which is where a small section of a CIPP liner can be installed where there is an issue in the pipe instead of lining the entire pipe. 
Cost to Replace a Cast Iron Drain

Cost of repairing (not replacing) a cast iron drain pipe under a house

  • The typical price range to repair a cast iron drain line is roughly $225 to $1,169. Depending on the accessibility, because the pipe is under the house, the level of difficulty will be increased. The price could increase to as much as $2,800. 

Cons of repairing a cast iron drain pipe under your home

Here’s why we don’t suggest repairing cast iron drain pipes. Repair is not a permanent solution, only being a temporary fix. Repair involves only fixing sections or a few feet of pipe at a time, meaning you will have to pay contractors a minimum fee each time. That makes the cost per linear foot of repair much higher. 

Cost of replacing cast iron drain pipes under your home

Homes built on concrete slabs will have sewer lines running underneath. The conventional sewer repair methods involve digging and trenching to access the old pipes. That means the concrete will need to be broken, tiles will need to be replaced, and your family will have to temporarily relocate. You’re not going to want or be able to live in a house with massive trenches in your living room.

Cost to Replace a Cast Iron Drain
Using the traditional dig and replace methods, the average cost can be from $50 to $450 per linear foot. The price to install brand new pipes throughout your home could run to $15,000 because of all the extensive work, such as cutting into walls or floors.
Trenchless sewer repair only requires one or two access points, often 4×4 pits on either side of the house. Or the access point can be made by pulling a toilet (we will put it back). Sometimes, some concrete needs to be chipped away under the toilet, but this is better than the alternative- a big ugly trench through your living room and kitchen. The collateral damage is next to none compared to the effects of traditional methods.
Trenchless sewer repair is broken up into two subtypes,
  1. Pipe liningA special, epoxy-impregnated liner is inserted into the old pipe, inflates, and creates a new pipe structure directly inside the old one. Pipe lining on average costs $80 to $250 per linear foot.
  • The price depends on a variety of factors, such as the condition of the pipe, ease of navigation, the amount of cleaning needed before the lining, and the accessibility of the pipe. The total prices do depend on how much pipe is being replaced, for example; 30ft of pipe at the median cost of $165 will be $4,950.
  1. Pipe burstingPipe bursting is where a new HDPE (high-density polyethylene) pipe is attached to a winch with a cone-shaped bursting head and pulled through the damaged pipe. The damaged pipe is broken apart as the new one takes its place. Pipe bursting is cheaper than pipe lining running from $60 to $200 per linear foot. Pipe bursting can replace 600+ of pipe. So for example, 30ft of pipe at the median cost of $130 will be $3,900.
Whatever your problem, we at New Flow Plumbing will assess the situation using a CCTV sewer camera inspection and give you the best solution. Contact us today and receive a quote.

About the Author: New Flow Plumbing Inc.

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