RV Black Tank Chemicals – How To and What to Use

When you bring up the subject of how to properly treat waste tanks, whether it is gray or black water tanks, RVers can get pretty heated about what the best method is. Everyone has their own opinion, and everyone will tell you they’ve been using their preferred method for umpteen years and have never had a problem.

The dirty little secret is…they are almost all correct. Because the truth is, while there are some principles that you need to follow, the exact chemical treatment you use can be a matter of what you prefer, how your black tank is situated, and what climate you typically camp in. There is no single right answer.

So for this article, we are going to cover the basic dos and don’ts, but we will also cover the most popular chemical treatment methods and what each has going for them.

The Dos and Don’ts – Principles that apply to every black tank.

So here is some basic information that will apply to everyone. Your black tank (and gray water tanks) are holding tanks. They are not septic tanks. You are only keeping the waste in them for a short period of time before disposing of them into a proper sewage system, be it city sewer or septic tank, where the waste will be properly broken down. This means any chemical does not need to significantly break down your waste, it only needs to aid the water in liquifying everything enough to pass out of the waste hose, as well as help control any odors that may leak back into the RV.

For this reason, certain old-school chemicals are to be avoided. Harsh chemicals that can damage your plastic holding tanks is obviously not good. Always be certain that any chemical you use does not include any caustic chemicals.

Also, avoid any chemical that will not break down organically or that contains formaldehyde. This is for two reasons. First, it is obviously not good for the environment. But as important, it can ruin a healthy septic system at the campground or dumping station by killing the bacteria needed to break down waste. This is why you will actually be banned from dumping in most sewage systems if you are using a formaldehyde or inorganic waste tank chemical.

So now that we have that out of the way, let’s cover the dos by covering many of the most popular treatments people use in their black water tank. All of these are acceptable depending on what works best for you.

Nothing at All

Because the black tank is a holding tank and not a septic tank, if your toilet paper and waste can break down fine in your system, then you may not need chemical at all. Water will normally do the bulk of the work breaking those solids down, so do make sure you provide your tank with ample water. It is tempting when conserving water and tank space, to not want to flush too long, but it will often be something you regret when it is dumping time since valves and hoses get plugged up without sufficient water.

Some reasons to not want to go without chemical can also occur. Typically some instances that occur include temperature and ventilation. You will notice in warmer temperature the tanks just smell more. So while you may get away with no chemical in cooler months, you may still want to use chemicals when the outside temperatures are warmer.

Also, depending on your motorhome or trailer, the position of the black tank and the vent pipe to the roof can determine if odors are passing back into your rig. You can do a few things to minimize this, though. Turn off the fan in the bathroom when flushing to keep the fan from pulling air from the black tank into the room. Also, upgrading the vent cap on your roof will increase the airflow direction into the toilet and out the roof vent as intended. Some RV manufacturers do this better, while others need the upgraded cap to avoid the backflow of sewer air.

The Camco Cyclone vent cap uses the slightest wind to greatly increase proper venting in your black tank or your gray tank (they also often share a vent). Whether you use chemical or not, this can help control odors in your rig significantly and it is easy to install.

sewer vent cap upgrade
The Camco Cyclone vent cap helps control odors.

Happy Camper – The most popular chemical and our favorite.

As we mentioned at the top, there is no one correct answer to what the best chemical is, but Happy Camper is our personal favorite. First of all, it is all organic. It is a bio-degradable mix of minerals that promote the good, non-smelling bacteria that helps break everything down.

What we like about Happy Camper, besides that it seems to control odors and break things down really well, is that you place the powder in the black tank through the toilet from a small container using the provided measuring cup along with a bowlful of water after you’ve emptied your black tank.

What this means is, not only is it very easy to store in a space-challenged RV, but you can fine-tune the amount used. They recommend a full scoop, but if you aren’t filling the black tank fully on a short trip, or the weather is pretty cool and you aren’t getting a lot of odors, you can place a little less of the powder in the toilet.

On particularly hot days, you might want to augment the amount with a little extra. While the chemicals that come in pre-measured packets are handy, you don’t have the flexibility to do those fine adjustments as needed.

Another benefit of the scoop and powder is, should you be having an issue with a particularly smelly gray water tank, you can place a small amount down the drain to help control odors in that tank as well.

It is easiest to buy Happy Camper online.

Happy Camper black tank chemical
As a powder, Happy Camper is compact to store and you can fine tune the amounts.

Packet-Style Chemical – There are several good ones.

Packet-style chemicals come in little self-contained capsules that you throw down the toilet and they dissolve, releasing the chemical. Two that are popular, affordable, and have biodegradable chemicals are the Porta-Pak treatment and the TST treatment. They are very similar and can be found in a number of places as well as online.

After dumping your black tank, you place one packet into the toilet along with a good amount of water to help dissolve the packet.

Bottled Chemical – Another option.

Bottled chemical can come in small, pre-measured bottles, or large bottles that you pour a certain amount into the black tank through the toilet, along with plenty of water. There are some very effective liquid chemicals like this, and we will suggest a good one, but be warned that this type of chemical is the most likely to contain either caustic or non-biodegradable chemicals — so read your labels carefully.

The other drawback is, because they are already liquid, they tend to be bulkier to store. However, large bottles do have the advantage of allowing some small amounts of additional chemical when odors require.

One of the better liquid chemicals out there and a good example of this category is the Campa Chem treatment. There are also a number of other good products as well, including the previously mentioned TST treatment.

The GEO Method – A little different way to do it.

There is a method that doesn’t use the pre-packaged chemicals many people swear by, and goes by the name of the GEO method. Basically it is a combination of standard fabric softener and mild detergent (either dish soap or laundry soap depending on who you ask) that you mix yourself and pour into the black tank through the toilet. The idea is that the two liquids keep things from sticking as you dump, as well as control odors.

We aren’t entirely convinced of its effectiveness, and one must be careful when mixing chemical items that aren’t intended to go together, but if used properly, there are many people that swear by this method. Since we may not be the best advocates of the method, I’m going to let someone who uses it explain the process in this short video by Mountain Modern Life.

Take your pick, or test out a few.

There is no reason you can’t try different chemicals or methods for your black tank to see what you like. Every experienced RVer has his or her own preferred method they will swear by, but they figured out what they liked best by trying one. So long as you stay away from caustic or inorganic chemicals, you can’t really go wrong.

Where can I find the items in this article?

Many of the items are available from RV stores, but we find that Walmart or Amazon tend to be cheaper. A few items are only available online. We’ve provided links to all the items we discussed so you can do more research or order the type that seems most appealing to you.

Are you an experienced RVer? What treatment do you like best for your black water tank? Join the discussion in the comments below.

Also check out:
4 Easy Ways to Find RV Dump Stations
RV Dumping Basics – Video
Gray Tank Valve – Leave Open or Closed? – Video

Be sure to join the discussion and leave a comment.
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