​Why Is There a Bad Smell Coming From My RV Sink? Diagnosis and Treatment Here

Christopher London
12 min readFeb 22, 2024

Why Is There a Bad Smell Coming From My RV Sink? Diagnosis and Treatment Here

I. Introduction

A. Brief introduction to the topic

B. Importance of addressing bad smells in an RV

II. Understanding Your RV Sink and Gray Tank

A. Explanation of the RV sink system

B. Overview of the RV gray tank and its role

III. Common Causes of Bad Smell From an RV Sink

A. Buildup of food particles and debris

B. Lack of water in the P-trap

C. The Anti-Siphon Trap Vent Device (ASTVD)

D. Problems with the RV gray tank

IV. How to Address & Prevent Bad Smells Coming from Your RV Sink

1. Regular cleaning and maintenance of the sink and drain

2. Ensuring the P-trap is always filled with water

3. Proper care and maintenance of the RV gray tank

4. Using treatments to eliminate odors

5. Treating Bacteria and Fungus Issues

V. Conclusion

Understanding and Addressing the Issue of Bad Smells Coming from Your RV Sink

Why Are There Bad Smells Coming From Your RV Sink?

Nothing’s worse than hitting the road and the further down it you get the more you notice your cabin smelling. Bad smells can come from a few places in RVs, and commonly the source appears to be the sink. Nothing puts a damper on a road trip like rolling down the highway in a sewer on wheels. If you’ve ever experienced this issue, you know exactly how bad it can be.

If you’re asking any of the following questions, this post will show you how to fix the issue.

  • Why Does My RV Sink Stink?
    -This is could be one of 5 things; a buildup of food and debris, a lack of water in P-trap, a faulty ASTVD, a problem in the gray tank, or bacteria in the hot water heater.
  • Why Does My RV Sink Smell Like Rotten Eggs?
    - This is most typically caused by bacteria in the gray tank or hot water heater.
  • Why Does My RV Suddenly Smell Like Sewer?
    - This is usually indicative of a faulty ASTVD, or issue with the gray tank.
  • Why is there a Bad Smell Coming from My Gray Tank?
    -This is could be one of 5 things; a buildup of food and debris, a lack of water in P-trap, a faulty ASTVD, a problem in the gray tank, or bacteria in the hot water heater.
  • How Do I Get Rid of Bad Gray Tank Odors?
    - By finding the source of the odor you can effectively treat the issue for example; if the issue was a faulty ASTVD, you can simply replace it, or if your Gray Tank has stubborn buildup you can use a treatment like the Extreme Cleaner to remove any buildup.

II) Understanding Your RV Sink and Gray Tank System

Before we delve into the causes of bad smells, let’s first understand the RV sink system. Your RV sink works much like the sink in a regular home. Water and waste go down the drain and into a holding tank, known as the gray tank. This tank holds the wastewater from your sink and shower until you can dump it at a designated dump station.

Most commonly if you’re smelling a bad odor from your RV sink — the source of the odor is coming from your gray tank. That being said, sometimes it can be tricky pin-pointing the actual cause of the odor. This post will cover diagnosing all potential sources of mysterious odors that appear to be coming from an RV sink and how to fix them.

III) What Causes Bad Smells Coming From Your RV Sink?

Now, let’s discuss what might cause bad smells to come from your RV sink. Here are some common causes:

a. Buildup of Food Particles and Debris:

If you’re not careful about what goes down your sink, food particles and other debris can build up in the drain or the gray tank. Over time, this buildup can start to decompose and produce a bad smell.

b. Lack of Water in the P-Trap:

Your RV sink should have a P-trap, which is a curved section of pipe that holds a small amount of water to block sewer gases from coming up through the drain. If this trap dries out, it can allow these gases to enter your RV, causing a bad smell or sewer smell.

c. The Anti-Siphon Trap Vent Device (ASTVD)

The Anti-Siphon Trap Vent Device is a plumbing component that prevents sewer gases from entering your RV or even your bricks and sticks home.

d. Problems with the Gray Tank:

If your gray tank isn’t properly maintained, it can become a source of bad smells. This can happen if the tank isn’t emptied regularly, if the vent for the tank is blocked, or if there is bad bacteria or mold growing from the inside top of your gray tank.

e. Bacteria in Your Water Heater:

If your RV smells like rotten eggs it is most likely bacteria in your water heater. Many RVers often mistake the smell as originating from the sink or shower, that is because the water is already contaminated coming out.

IV) How to Address and Treat Bad Smells Coming From Your RV Sink?

If you’re dealing with bad smells coming from your RV sink or Gray Tank, here are some steps you can take to address the issue:

1. Clean Your Sink and Drain Regularly:

Regular cleaning can help prevent the buildup of food particles and other debris. Use a good quality drain cleaner and a brush to clean the sink and drain.

Regularly Flushing the Gray Tank

Your RV’s gray tank, which holds wastewater from your sink and shower, can be a major source of bad smells. Like we mentioned above, over time, food particles, grease, and other debris can accumulate in the gray tank, leading to some pretty bad smells. Regularly flushing your gray tank is crucial for preventing this buildup and keeping your RV smelling fresh. After dumping the tank, consider filling it with clean water and dumping it again to ensure it’s thoroughly cleaned. Doing this regularly can significantly reduce the chances of bad smells emanating from your sink.

2. Keep the P-Trap Filled:

To prevent sewer gases from coming up through the drain, make sure the P-trap is always filled with water. You can do this by running a small amount of water through the sink after using it.

Regular cleaning and maintenance of your RV sink can go a long way in preventing bad smells. This includes not only cleaning the sink itself but also the drain and P-trap. Using a good quality drain cleaner, but nothing too harsh like bleach, and a brush, give your sink and drain a thorough cleaning regularly. Also, ensure that the P-trap is always filled with water to prevent sewer gases from coming up through the drain.

Avoiding Disposal of Food Particles in the Sink

While it might be convenient to wash food particles down the sink, this can lead to problems down the line. These particles can accumulate in your gray tank and start to decompose, producing bad smells. To prevent this, try to scrape your dishes into a trash can before washing them in the sink. Using a sink strainer can also help catch any food particles that might otherwise end up in your gray tank.

3. The Anti-Siphon Trap Vent Device (ASTVD)

Solving the Mystery of the Bad Smell Coming From Under the Sink

We should note that there could be a mystery culprit next to the P-trap that could be the cause of sewer smell.

Unmasking the Culprit: How the Anti-Siphon Trap Vent Device (ASTVD) Can Cause a Bad Smell Under Your Sink

The Anti-Siphon Trap Vent Device is typically installed under the sink and allows air to enter the plumbing system to balance the pressure when water drains from the sink. However, it’s designed to close when not in use to prevent sewer gases from escaping into your RV.

Replacing the ASTVD under your sink

If you suspect that your ASTVD is causing a bad smell under your sink, here are some steps you can take to solve the issue:

a. Inspect the ASTVD:

The first step is to inspect the device. Look for any visible signs of damage or debris that might be causing the device to malfunction. The rubber seal could even be bad.

b. Clean the ASTVD:

If the device is clogged with debris, cleaning it might solve the issue. You can do this by unscrewing the device and using a small brush to clean the inside. Be sure to replace the device properly after cleaning.

c. Replace the ASTVD:

If cleaning doesn’t solve the issue or if the device is damaged, you might need to replace it. ASTVDs are relatively inexpensive and easy to install, so this can be a simple solution to the problem. You can find this part at most hardware stores like ACE Hardware or even Amazon for $6.67.

Oatey 39012 1.5 in. NPT ABS in-Line Vent d. Call a Professional:

If you’re not comfortable dealing with plumbing issues or if the problem persists after cleaning or replacing the ASTVD, it might be best to call a professional plumber. They can diagnose and fix the issue, ensuring your plumbing system is functioning properly.

By understanding how the Anti-Siphon Trap Vent Device can cause this issue and how to solve it, you can keep your RV smelling fresh and your plumbing system functioning properly.

4. Maintain Your Gray Tank:

Regularly empty your gray tank and make sure the vent is clear. You can also use a tank treatment product to help break down waste and control odors.

Using RV Odor-Eliminating Products

There are many products on the market designed to eliminate odors in your RV’s plumbing system. These include tank treatments that help break down waste and control odors in your gray tank, as well as drain cleaners that can remove buildup in your sink and drain. Using these products as part of your regular maintenance routine can help keep your RV sink smelling fresh.

Yes, we do have our own odor eliminating product that we’re pretty fond of and highly recommend.

Using Happy Campers Holding Tank Treatment: Your Solution to Preventing Odors in RV Gray Tanks

RVing is all about enjoying the freedom of the open road and the comfort of your home-on-wheels. However, maintaining the freshness and cleanliness of your RV, particularly the gray tank, can sometimes be a challenge. One product that has proven to be a game-changer in this aspect is the Happy Campers Holding Tank Treatment. In this blog post, we’ll guide you on how to use this product to prevent odors in your RV gray tanks.

Happy Campers Holding Tank Treatment is a highly effective odor-eliminating product designed for RV gray and black tanks. It’s a proprietary blend of minerals and micronutrients that is septic safe and safe for RV plumbing. The treatment works by breaking down waste and promoting the growth of beneficial bacteria, which helps to eliminate unpleasant odors.

How to Use Happy Campers Holding To Prevent Bad Smells in an RV Gray Tank

Using Happy Campers Holding Tank Treatment is a simple process. Here’s a step-by-step guide:

a. Determine the Required Amount:

The amount of Happy Campers treatment you’ll need depends on the size of your gray tank. The general rule is one scoop (provided with the product) for every 40 gallons of tank capacity.

b. Prepare the Treatment:

Fill your toilet or sink with water and add the required amount of Happy Campers treatment. Stir until the powder is fully dissolved.

c. Apply the Treatment:

Pour the dissolved treatment down the sink or shower drain. This will distribute the treatment throughout your gray tank. (For a 40 gallon tank you should have 1 scoop of product and 2–3 gallons of water in the tank to start)

d. Let It Work:

Once the treatment is in the tank, it will immediately eliminate odors and start to break down waste. For best results, make sure you have enough water in the tank and just keep the Happy Campers in there until you dump the tank.

e. Repeat as Needed:

Apply the Happy Campers treatment each time you dump your gray tank to keep it fresh and odor-free.

5) How To Get Rid of Bacteria and Mold in an RV Gray Tank

RV holding tanks have a lot of good bacteria that help break down waste and control odor similar to a septic system. That being said, not all bacteria is good and sometimes when we put enough food or other items down the sink, well the good bacteria can get overwhelmed and you’ll notice it from the odor.

This bad bacteria along with mold, unlike the good bacteria found in your tanks often grows from the top of the tank down. So, you can imagine this stuff building up above the water line just wreaking. When this happens standard odor eliminators aren’t going to cut it. You will need to to a thorough cleaning of the gray tank.

To get rid of stubborn odor causing bacteria and mold in an RV gray tank follow these steps:

1. Turn off the fresh water. 2. Mix 1 entire container of Extreme Cleaner into a bucket full of water. Flush the product and water down your sink. 4. If you are mobile: Drive your camper/trailer around for a good 45 minutes to make sure what’s in the holding tank gets swashed around real good. 4b. If you are stationary (can’t drive around): Add as much hot water into your holding tank along with the full container of Extreme Cleaner. Let this sit in your tank for 24–72 hours. Better results for 48–72 hours, but we can’t always wait that long, can we? 5. Dump your black tank and rinse. 6. Use your built-in rinser, a tank wand or backflusher to make sure your tank is clear. 7. Turn your fresh water valve back on. 5. Address and Clean Hot Water Heater:

5b) How to Get Rid of Bad Smelling Bacteria and Mold in Your RV Hot Water Heater

As stated by Cruise America ,

Your RV’s water heating system usually comes equipped with a magnesium or aluminum anode rod, meant to prevent corrosion of your water tank.

As bacteria and sulfur microbes in your water tank interact with the rod, hydrogen sulfide is produced and interacts with the magnesium or aluminum, and it is this interaction that creates the rotten egg smell.

Understanding the Issue

Bacteria and mold thrive in warm, damp environments, making your RV hot water heater an ideal breeding ground. If left untreated, these microorganisms can multiply and contaminate your water supply, leading to potential health issues and unpleasant smells.

How to Treat Bacteria and Mold in Your RV Hot Water Heater

Treating bacteria and mold in your RV hot water heater involves a few simple steps:

1. Drain the Water Heater:

The first step is to drain your water heater. Turn off the heater and let it cool down. Once it’s safe, open the drain valve and let all the water out.

2. Prepare a Cleaning Solution:

Next, prepare a bleach solution to disinfect the water heater. Mix one cup of bleach with one gallon of water.

You Can also use the Extreme Cleaner Product as a hot water tank cleaner. Mix 1 container of Extreme Cleaner with 1 gallon of water.

3. Fill the Water Heater with the Cleaning Solution:

Close the drain valve and pour the bleach or Extreme Cleaner solution into the water heater. You can use a funnel to make this process easier. Once the tank is filled with the solution, turn on the water heater and let it run for a few minutes to circulate the solution.

4. Let the Solution Sit:

Turn off the water heater and let the solution sit for at least 24–48 hours. This will give it enough time to kill any bacteria and mold in the tank.

5. Drain and Rinse:

After the cleaning solution has done its job, drain the water heater again. Then, fill it with clean water and drain it twice more to rinse out any remaining cleaning solution.

6. Repeat if Necessary:

If you still notice an odor or signs of bacteria or mold, repeat the process.

In Conclusion

Treating bacteria and mold in your RV hot water heater is a crucial part of maintaining a safe and healthy RV. By following these steps, you can ensure your water supply is clean and free from harmful microorganisms. Remember, a well-maintained RV is a happy RV. Don’t let bacteria and mold in your hot water heater put a damper on your adventures.

In conclusion, preventing bad smells in your RV sink is all about regular maintenance and smart practices. By regularly flushing your gray tank, avoiding disposal of food particles in the sink, keeping your sink and drain clean, and using odor-eliminating products, you can keep your RV smelling fresh and make your adventures more enjoyable.

If you are experiencing any foul smelling odors coming from your RV sink or gray tank, just follow the steps in this article to treat and prevent these issues, ensuring a safe and enjoyable RVing experience. Happy RVing!

Originally published at https://www.happycampers.store.

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Christopher London

Chris London, Owner/Marketing Director for Pixel Productions Inc, is an expert in brand building, Ecommerce Development, and online marketing.