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How to Keep Your RV's Blackwater Tank Healthy

Updated on August 21, 2016
TIMETRAVELER2 profile image

I am an avid RV enthusiast who has traveled, lived, workcamped and volunteered nationwide for more than 50 years and still am going strong!

For people who own RVs, problems with the black water (sewage) holding tank can be the most frustrating and upsetting.

Even if you do regular cleaning and use effective and safe products, these things may not be enough to keep waste water tanks functioning properly, because maintenance doesn't address all the ways this tank can malfunction.

This article points out these problems and shows you the best ways of dealing with them.

How to keep your RV's black water holding tank in good working condition.
How to keep your RV's black water holding tank in good working condition. | Source

Malfunctioning Tank Monitors

Tank monitors are not always reliable, especially on older motor homes and campers.

It will not matter about this as long as you remember to dump daily, but if you forget to do this, your nose most likely will remind you that it’s time to do some cleaning.

Don't put off cleaning or you could be creating serious problems for yourself.

Putting Inappropriate Objects in the Toilet

RV plumbing systems clog easily. It is always a mistake to put anything into toilets except biodegradable toilet paper.

Never try to flush tampons, paper towels, sponges or other inappropriate items down an RV toilet, because they cause expensive and inconvenient problems.

Don't use regular household toilet paper either. it will clog your tank as fast as those inappropriate items I just mentioned. Biodegradable paper is more expensive but can save you thousands of dollars in repairs.

My husband and I never travel without biodegradable toilet paper because we’ve learned the hard way (as you will see shortly) about the problems that come from trying to cut corners by using regular types of toilet paper!

Ignorance About Tank Size

Few people realize that tanks vary in size from one coach to another.

Check your manuals to find out how big your own tanks are so you can correctly judge how often you will need to empty them.

If you do not have your manuals, you can find the information you seek on the internet or by contacting the parts department of your local RV dealer.

People sometimes assume that large coaches have big tanks, but this is not always true. It’s best to know what you’re dealing with so that you can keep sewage from backing up into your coach and flooding it.

Differences in Fill Methods

Toilet tanks fill either from the toilet, shower, bathroom sink or some combination of the three.

The more inflow sources there are, the more quickly the reservoirs fill.

Those that fill quickly must be emptied more often, so to avoid flooding problems, check your manuals or ask the manufacturer the specs of your particular travel unit.

If your tank is clean but still smells, it's time to investigate other issues that may be causing odors.
If your tank is clean but still smells, it's time to investigate other issues that may be causing odors. | Source

Odors That Persist Even After Cleaning

Under normal circumstances, if you follow the directions in How to Dump, Clean and Maintain Your RV‘s Blackwater Tank, you should never smell tank odors in your coach.

If you do, it is possible you have a more complicated issue such as:

  • leaking valves
  • clogs
  • poor plumbing design
  • broken sewer pipes

If you are handy, you may be able to address and fix such problems yourself.
If not, you may require the help of an RV mechanic.

Before you seek outside help, it would be a good idea to try a product that can help you to know if your problem is caused by normal tank problems or one of the above issues.

Extreme Tank Cleaner

Extreme Tank Cleaner is a product can decimate those hardened deposits that can make your coach smell and cause clogs when sidewall sludge breaks off and falls into waste water pipes.

I have not used it personally, but people who used this product say that it is very effective in cleaning off the type of heavy sludge in their tanks that can break off and cause clogs and block sensors.

I have yet to see another product that works as well or in the same way as this one.

It is expensive and should only be used as a last resort before researching other sources of sewer odors or calling in an RV repair man.

People say the secret is to use it exactly per the company's directions.

EXTREME CLEANER by Happy Campers - RV & Marine Extreme Tank & Sensor Cleaner
EXTREME CLEANER by Happy Campers - RV & Marine Extreme Tank & Sensor Cleaner

This is a product made specifically for removing sludge build up from RV blackwater tanks. It takes some effort to use, but will get the job done for you.


Leaking Valves

Sometimes when there is a valve leak or broken sewer pipe, the odors seep into the walls of your coach.

So, even after you have deep-cleaned the tank, your coach still smells.

it is hard to figure out where the smell is coming from, but the most obvious culprit is a leaking valve.

Here are some fixes that may deal with this problem.

  • Install an RV cyclone sewer plumbing vent that functions in the same way as the one you use in your attic. It will suck those smells out of your RV and exit them through the vents,
  • Repair or replace a damaged sewer vent.
  • Fix a broken or cracked sewer pipe.

It is possible that you may even have to do all three, but once you do, your coach should no longer smell.

Camco 40595 White Cyclone Sewer Plumbing Vent
Camco 40595 White Cyclone Sewer Plumbing Vent

Installing one of these cyclone sewer plumbing vent cleaners is one of the best ways to rid your coach of noxious odors. It simply sucks them up and out of your walls!



Waste water tanks can easily become clogged if they are not properly used and maintained.

How to Clear an RV Toilet Clog shows you how to repair a stopped-up system yourself, but doing this is a dirty, messy job that does not always work. You only have to try to clear a clog yourself once to realize you don't want to do it again, and you had better make some changes about what you put into your toilet.

Poor Plumbing Design

In some motor homes, the very structure of the plumbing system can be a problem.

For example, the diagrams of one brand show that it has a 45 degree turn in the pipes. Thus, heavy bowel movements or using too much toilet paper at one time can clog the system.

Furthermore, sludge build up in that area can sometimes break off and get stuck in the valves and damage them.

Check your specs to make sure this is not your situation. If it is, take great care with what you put in your toilet!

Broken Sewer Pipes

Sometimes, due to sloppy construction methods or road vibration, sewer pipes can develop cracks or even break off.

When this happens, tank odors fill your coach, but you cannot find their cause.

  • If you are handy, you may be able to remove part of the wall board behind your toilet so that you can see if a pipe has cracked or is broken and then fix it.
  • If not, you will need to have a repair person do this job for you.

Sewer Tank Damage

Sewer tanks crack due to overloading with liquids, accidents that cause flying debris to forcefully hit them, or aging.

You can generally avoid the first two problems by

  • never allowing the reservoir to completely fill before draining it
  • making sure that your tires are always properly inflated and
  • taking great care when driving.

But if your coach is old, there’s not much you can do about the third problem, other than to inspect it regularly for damage and making repairs where necessary.

Keeping Your Sewer Tank Healthy Takes Effort

If you clean your tank thoroughly, and it still emits noxious odors, investigate the problems I have discussed here to see if one of them is yours.

Normally regular maintenance will keep your tank in good condition, but if not, it may be time to take more serious action.

Good Luck!

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