One of the great tragedies which face any homeowner is that nothing lasts forever. Even seemingly solid materials have a finite lifespan and cast iron plumbing is, unfortunately, no exception. While you can expect to get many years out of you pipes, exactly how long does cast iron pipe last?
What Are Cast Iron Pipes?
Before we set about answering the question of how long do cast iron pipes last, let’s have a little history lesson. Until the 1970s, cast iron was the go-to choice for much of our domestic, commercial and public plumbing. It was favored because it’s strong, durable and fire-resistant and, as an added bonus, it’s pretty good at dampening the sound of running water too.
This means that if your home pre-dates the 1970s, there’s probably at least some cast iron pipework left in there. There were also a good number of years overlap between the phasing out of cast iron plumbing and the proliferation of copper.
How Long Does Cast Iron Pipe Last
One of the main reasons that cast iron was so favored was that it’s an incredibly hardy material. You can reasonably expect to see 50-100 years of service (depending on local conditions) out of a well maintained system.
Factors Which Affect the Lifespan of Cast Iron Pipes
Of course, that’s a 50 year gap between shortest and longest lifespan, so what is it that creates this potential variance? Well, there could be any number of factors at play, including:
- Soil conditions: burying a length of metal pipe in acidic or waterlogged soil will have different results from more alkali, drier soil.
- Water quality: pretty much all drinking water has a certain level of contamination in the form of minerals and elements. Some of these will slowly start to cause build-ups and corrosion in cast iron plumbing.
- Installation quality: while we might think of the tradesmen of the past as possessing a special level of craftsmanship, the truth is there are as many dodgy installations from the 1970s as any other era.
- Environmental moisture and humidity: pipes in humid conditions corrode faster than ones which are kept dry.
- Pipe quality: a flimsy, thin pipe won’t last as long as a more solid one.
- Frequency of use: the more you use a plumbing system, the more wear and tear you can expect. This is particularly noticeable in high-use households.
- Level of maintenance: unsurprisingly, a properly maintained system will last longer than one that’s been ignored for 50 years.
Even under the best possible circumstances, deterioration is bound to occur eventually. As we approach the 50 year anniversary of cast iron plumbing, we’re seeing more and more systems succumb to the ravages of time.
Common Signs of Aging or Deteriorating Cast Iron Pipes
Now that we’ve answered the question “how long does cast iron pipe last?”, what are the warning signs of yours coming to the end of its natural life?
Discoloration and Rusty Water
Pipework can corrode from both the inside and out. One common sign that your cast iron plumbing is coming to the end of its lifecycle is the presence of rusty, orange water. Rust itself isn’t dangerous, but a corroded system could be letting in all kinds of nasties.
Frequent Clogs or Slow Drains
As pipework ages, it often gets jammed up with all kinds of debris. This goes double for cast iron which can narrow as it corrodes. This often presents itself as problems with drainage as the water struggles to run down the pipework as it once did. Keep an eye out for chronic clogging, slow drains and backups.
Leaking pipes
Leaks forming around joints or even pinholes forming in the body of the pipework are a sure sign of deterioration. As the pipes continue to age, these will get worse with time, potentially leaking gallons of water into your home.
Sewer Odors
We rely on our plumbing to take the nasty stuff away every bit as much as we need it to bring the clean stuff in. When waste pipes start to degrade, there’s a risk that they’ll crack, allowing sewer gases to escape.
Water Damage On Walls And Ceilings
Much of your home’s pipework is tucked neatly away between the drywall or under the floor. While this keeps things neat and tidy, it can mean that deteriorating pipework goes undetected until damp spots start appearing. Keep an eye out for damp patches, stains or mold and investigate at the first sign.
Risks of Keeping Old Cast Iron Pipes
Far from simply being a bit of an inconvenience as your plumbing becomes less efficient, deteriorated cast iron pipes can cause a lot of damage to your home and health. Some of the risks include things like:
Structural Damage
A leaky, corroded pipe can do more than create an unsightly damp patch. Water will ruin plaster, rot wood and, given enough time, damage your foundations. This can lead to a variety of problems, up to and including collapse in extreme circumstances.
Health Risks
A pipe with holes in it doesn’t just let water out; it also lets contamination in. This will impact your home’s water quality and could lead to your family getting sick. Even if it doesn’t, leaks create the perfect conditions for mold growth, especially in places like basements. This can have some pretty serious health consequences.
Increased Costs Over Time
Leaking pipes push up your utilities (and not just your water bill- a damp home is harder to heat too) and the longer you leave them, the more the repairs will cost. Older pipes will need more and more frequent repairs as parts fail and require replacement. Eventually these constant repairs will cost more than a full replacement.
Increasing Risk Of Major Failures
As the system continues to age, the risk of a catastrophic problem increases. Major pipes bursting or sewage leaks can wreck absolute havoc on your home and will be expensive to put right again.
Repair Vs Replacement
As with any system in the home, the question of repair vs replacement is a tricky one to answer. Smaller, isolated problems can likely be repaired through either replacing that part or relining the pipe. Eventually though, the scales will tip and the number of repairs needed will mean that a full replacement is the economically sensible choice.
If you’re facing more frequent issues with your cast iron plumbing, you’ll have to decide when full replacement makes sense. Consider things like:
- Frequent leaks
- Signs of extensive corrosion
- Multiple areas showing signs of deterioration
Replacement Options
Cast iron plumbing doesn’t have to be replaced like-for-like. It can be upgraded to more modern materials like ABS or PVC, which are more resilient and resistant to corrosion. They’re also a good deal easier to maintain, keeping costs down after the initial buy-in.
It’s also worth considering if you need to replace the whole plumbing system in one go. It’s often possible to do things bit-by-bit rather than ripping everything out and starting again. Whether this is the right route for your home depends on the extent of the deterioration and how much of an investment you’re willing to make.
Replacement Process for Cast Iron Pipes
If you do opt for replacement over repair, the process should go something like this:
Inspection And Assessment
First things first, you need to know what you’re looking at. Your cast iron plumbing should be properly inspected before any other step. This allows you and your plumbers to make informed decisions about the work you’re undertaking.
Plumbers might make use of specialist cameras and hydrostatic testing to get a detailed view of the current system and potential problems in replacing it.
Planning the Replacement
After the initial survey, your installers should provide you with a detailed plan. This will map out the work and routes the new pipework will follow. It also gives you the chance to decide whether to replace things in full or work section by section.
Consideration will be given to things like accessibility and the layout of your home. This is a good opportunity to consider future needs as well.
Choosing the Right Materials
Modern plumbing offers a range of potential materials. Some are better suited to some tasks than others. ABS is a common choice for supply pipes, being durable, flexible and easy to work with. PVC is often employed for waste purposes, being all but invulnerable to aging but not particularly flexible.
Getting the choice right here means that your replacement system should last a lifetime.
Replacement and Testing
The final steps are the installation of the new system itself. It will probably involve digging, lifting floorboards and cutting into walls, but the final results should be well worth the disruption. Before the plumbers sign off on their work, the system should undergo rigorous testing to ensure that it’s up to standard.
Benefits of Replacing Old Cast Iron Pipes
While replacing an old cast iron plumbing system is likely to be disruptive, the results are worth the mess. You can expect:
- Improved water quality: Modern pipes vastly reduce the risk of contamination and rusty water. The results are improved taste and quality.
- Increased home value: Updated infrastructure is always a good selling point.
- Reduced risk of plumbing emergencies: New pipes reduce the risk of problems happening, offering fantastic peace of mind.
- Greater energy efficiency: Damp homes are harder to heat and inefficient plumbing puts a strain on appliances like water heaters. Upgrading can help cut your energy bills by a substantial amount.
So, with a lifespan which is nearing its natural end, is it really worth upgrading your old cast iron plumbing? You’ll have to decide that for yourself.