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How Much Does It Cost To Replace An RV Black Water Tank?

cracked water tank - what is the cost to replace an RV black water tank
Cracked RV black water tank. Photo from

How Much Does It Cost To Replace An RV Black Water Tank?

Few things in RV life are worse than a leaking black water tank. The cost to replace an RV black water tank can get very high, and the mess created by a damaged tank can be extremely unpleasant. Thankfully, a broken tank can be replaced or repaired by a professional. You may even be able to fix or repair it yourself if you’re handy. 

An RV black water tank, also known as a holding tank, is one of two tanks in your RV that stores wastewater. The black water tank specifically holds the wastewater from your toilet. The rest of the wastewater, such as from your sink and shower, drains into what’s known as a grey water tank.

Even the best-maintained black water tank will eventually need replacement or repair. But just what is the cost to replace or repair an RV black water tank?

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What Is The Cost Of An RV Black Water Tank Replacement?

If you think your RV holding tank may have sprung a leak, the first step will be to diagnose the leak. You’ll want to park your RV on a surface you can clearly see leaks on, such as a concrete driveway. Then you can better see exactly where the leak originates. 

The next step is to crawl under your rig with a flashlight and an inspection mirror to see if you can see the issue with your tank. Inspect the tank to see if you can find the source of the problem. Look for any cracks or pinholes in the tank. The source of the leak could also be a pipe attached to the tank.

Once you’ve nailed down the source of the problem, your next step will be DIY or get professional help. The cost to replace an RV black water tank will vary greatly depending on your rig and your RV mechanic. But you’ll be looking at at least a few hundred dollars up to $1000 or more. You’ll have to get a quote from a mechanic to know an exact cost, but there are a few factors that will affect the cost to replace your RV black water tank. 

What affects the cost of an RV black water tank replacement or repair?

The first factor is the type of plastic your RV holding tank is made of. Two main types of plastic will be used for a black tank: LDPE plastic and ABS plastic. The type of plastic will affect what kind of repairs can be done (if any).

If repairs aren’t possible, you’ll need to replace the holding tank. If you have a standard-size tank, you’re probably looking at a cheaper, faster replacement. But if not, you may have to pay extra to adapt a tank to fit or have a custom tank built. At a minimum, a new tank will cost around $100 and can go up to $300 or more

After the cost of the new tank, you’ll also have to pay the mechanic’s labor costs, which can vary greatly. Labor costs can be as little as $65 per hour – all the way up to $189 per hour and beyond!

You’ll also want to consider how complicated your sewer system is. A more complicated system means a more complicated repair. This means higher costs to replace your RV black water tank.

Can I repair or replace my RV black water tank myself?

If you want to save money on the costs to replace an RV black water tank, DIY may be an option for you. Most folks will likely be limited to simple repairs. However, if you have the right tools and skills, replacing the black water tank yourself may be a possibility. 

Remember those two kinds of plastic, LDPE and ABS? You’ll need to know which one your RV holding tank is made out of to get started on repairs. 

Topical adhesives

The first option for repairs is topical adhesives, which can be used on either kind of plastic.

These are epoxies that can be used to plug holes or cracks in the tank and are commonly found as “tank repair kits” online. However, this is a temporary fix at best.

Chemical welding

If you have an ABS plastic tank, then you may be able to repair using chemical welding. This is a chemical that melts the plastic to create a strong bond that can be easily applied using a paintbrush. However, this method won’t work with LDPE plastic. 

Thermal welding

If your black water tank is made of LDPE plastic, your best bet will be thermal welding. This is the use of heat to melt the plastic together. This can be done with a variety of methods and equipment. 

It’s labor-intensive and requires patience and skill, but it is still possible to do DIY thermal welding. Kits can be found online for around $200. Once you know how to use them, they can be great for simple repairs. 

RV Black Water Tank Replacement Process

If you want to DIY an RV black water tank replacement, you may be looking at a bit of a process. At its simplest, the process is:

  • Drain and remove the old tank
  • Attach the hoses to the tank
  • Seal up the connection with caulk

However, things can get much harder and dirtier than that.

Now you know the cost to replace an RV black water tank

Having to replace or repair a black water tank isn’t fun, but it’s something that many RV owners will experience eventually. There are a number of factors involved that will affect the cost to replace an RV black water tank, but at the end of the day, you’re likely looking at at least a few hundred dollars at the mechanic. But, if you’re especially handy, DIYing your repairs is possible, and being able to fix your own tanks can save you money in the long run.

Track your RV maintenance and repairs

Make sure you keep track of all your RV maintenance and repairs with an online tool such as RV LIFE Maintenance. Not only can you keep all of your documents in one place, but you’ll also receive timely reminders when maintenance is due to help you avoid costly repairs and potentially serious accidents.