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Help Choosing Caravan / RV Toilet Chemicals

Article by Peter Smith - Caravans Plus
Read Time: 7 mins

We have an article that describes features to look for in Portable Toilets

We also describe the differences in Built-in Cassette Toilets

Do I need toilet additives and which are best?

It is possible to use a portable toilet for just overnight use without any chemicals at all. This can be useful if you need to empty contents into a composting type toilet where chemicals are prohibited. Any longer than one nights use or if used for more than a wee, then yes you will need an additive especially to rinse out.

Which additives are best for the environment?

There is not a black and white answer for this question. There are definite options available depending on your preference and depending on where you will be disposing of the waste.

Toilet additives can come in very ECO-friendly versions or others that are not so friendly but have other benefits. More on this after we look at where you can empty your toilet waste which is also described as Black Water.

Where will I empty my toilet waste?

Many first time users worry about disposing of the waste, but it can be quite easy and hygienic. Most modern holding tanks can be carried with just one hand and feature large non-splashing dump spouts and venting buttons. It is certainly less effort than a number of trips to the communal loo, plus you can have your own soft loo paper, even with a print if you fancy.

The biggest area of concern when disposing of toilet waste is if the additives (sounds better than chemicals) will effect the toilet system that they are added to. This can be confusing because there are a number of completely different toilet systems and lot of different opinions.

Finding Dump Points

Unless you want to dig a hole, 50m away from any water course, you should look at the more sustainable options. Look for these blue signs while traveling or check out these smart phone apps that will locate your nearest dump point.

How to find a dump point

Try WikiCamps (my favorite) or Caravan Helper: Find Dump Points. These will find a Dump Point close to you on a map.

If you will be emptying your waste tank into a dump point connected to a sewer system you can use any of the toilet additives available from CaravansPlus.

Using Dump Points

Tips on using dump points

Dump Points are becoming more and more widespread in Australia as a free service to the RV public. Many caravan parks also provide them for their customers, or for others for a small fee.

These Dump points can be used for portable toilets, cassette toilets and also RV's that contain built-in holding tanks that empty via a hose.

These should always be rinsed after use and left with the lid closed. Take care not to drop your dump cap but if you do, we can help out with any spares.

Using Amenity Blocks

While some caravan parks may permit you to empty the waste contents into their toilets, this is certainly frowned upon by some caravan parks and by other amenities users. Any septic safe additive will not be a problem if they are disposed of in flushable loo's.

Using Pit Toilets

The disposal of waste that includes sodium per-carbonate, as detailed below, in the standard concentrations is fine. You may use Septic Safe additives, BUT they must be used in the correct concentrations and have sufficient liquid at time of disposal. Pouring in a bottle of undiluted septic safe additive into a pit toilet is too concentrated and will have an adverse effect on the breakdown of the waste in often dry pit toilets.

Using Composting Toilets

This is a definite no-no. While the emptying of any waste is forbidden, it is the chemicals that are really the problem.

Types of Additives

Anything that is added to the flush tank or waste tank is classed as an additive, how bio-degradable or effective it is, is another thing altogether.

Generic Additives

Sodium per-carbonate is an effective chemical that is found in a number of brands of Laundry soaker's. The strength varies from 25% to 35% which is ample. 100% is available for sterilizing purposes from specialty suppliers but can cause too rapid a reaction in a waste tank. The following images show a selection of Laundry soaker's that would all work well.

Sodium Percarbonate powders

A small problem with these is the need to continually add a small top-up to the waste tank, as the chemical conversion to oxygen, water and sodium carbonate is quite rapid. Some commercial toilet products use the same chemicals but at a slower release rate. Odour-B-Gone is a tablet example of these commercial toilet products.

Both these options provide an eco-friendly solution, without any added fragrance. A combination of both may give a more balanced result over a number of days using a half tablet for slow release but boosted when required with a teaspoon of the less expensive laundry soaker. The addition of the laundry soaker to the flush tank is NOT recommended as it starts its chemical reaction as soon as it gets wet.

Where a toilet is used only for urine the above will have no effect. In this case we recommend the addition of a dash of white vinegar.

Flush tank additives

While all portable toilets have a separate flush tank, some built-in cassette or holding tank toilets use the main RV water tank to supply the water for flushing, so an additive cannot be used.

A spray bottle filled with the additive can be used, or Thetford produce a pre-packaged spray for this purpose.

Thetford Aqua Rinse Spray Bottle 500ml - Suit Toilets Without Flush Tank

Thetford Aqua Rinse Spray Bottle 500ml - Suit Toilets Without Flush Tank

12 In Stock Now.

Where an additive is placed in the flush tank, its purpose can be one or more of the following:

In addition to the above, it should be septic safe.

Thetford Aqua Rinse Concentrate - Flush Tank Additive- 750ml

Thetford Aqua Rinse Concentrate - Flush Tank Additive- 750ml

9 In Stock Now.

Waste tank additives

Environmentally sound waste tank toilet additives should be a major consideration. There are still toilet chemicals available in the market that we do NOT recommend. These contain formaldehyde which is toxic to the environment. CaravansPlus does NOT sell any chemical that contains formaldehyde.

Septic Safe

Any camper or caravaner who is interested enough to visit a National Park should also be concerned enough to look after the facilities provided.

In the rare locations where National or State Parks provide flushing toilets, these are usually the Septic style. There are a number of additives that are classed as Septic Safe and will not damage the bacteria that make the septic systems operate. These products will always state they are Septic Safe. Any specific toilet waste additive that does not state it is Septic Safe, should not be disposed of into a septic system. Some may say Eco-friendly or Bio-degradable but at CaravansPlus unless they specifically say Septic safe we advise to be wary.

As a general rule GREEN additives are the most environmentally friendly. Generally BLUE additives are a chemical that inhibit bacterial growth and mask the odor. If we had to give a simple recommendation that looks at conventions rather than regulations we would say use GREEN if you will use Septic systems at any stage, or BLUE if you will only use Dump Points.

You can always prolong your stay in a National or State park by having a spare waste tank. You would need to use a waste tank additive until you find a suitable dump point.

Liquid, Sachets, Tablets or Napisan

It does come down to personal choice on the method of including your additive.

The liquids require no additional dissolving, however they still need some flushed water to correctly circulate the additive. Getting the correct measure can be a bit of a guess unless you have a measuring cup or use one of the brands that includes measuring marks on the bottles.

Thetford Aqua Kem Green Concentrate - Waste Cassette Tank Additive - 750ml - Septic Safe

Thetford Aqua Kem Green Concentrate - Waste Cassette Tank Additive - 750ml - Septic Safe

11 In Stock Now.

Sachets are pre-measured and also require some flush water to properly dissolve. Very easy to use.

Walex Bio-Pak Express Green - Waste Cassette Drop-In - 15 Sachets - Septic Safe

Walex Bio-Pak Express Green - Waste Cassette Drop-In - 15 Sachets - Septic Safe

141 In Stock Now.

Tablets will slowly dissolve and a little testing maybe required to find what works best for you. However they are very environmentally friendly.

Odour-B-Gone RV Toilet Tablets - 25 x 8g Tablets - Septic Safe

Odour-B-Gone RV Toilet Tablets - 25 x 8g Tablets - Septic Safe

17 In Stock Now.

The granular laundry soaker available from supermarkets are measured into the waste tank, and then supplemented with a small dose at each use. If slide value seals become less flexible they are readily replaceable on most brand name toilets.

Toilet Tissue

Is it necessary to use special toilet paper in a chemical toilet? Yes and no. It is certainly possible to use normal toilet paper in a chemical toilet, however there is a marked difference in time taken for the toilet tissue to dissolve.

Where a straight thru slide valve is used like in the portable toilets, this will have little effect. The problems mostly occur with the cassette waste tanks that have a mechanism within the tank. These moving parts are susceptible to fouling from the toilet tissue that does not dissolve properly. There is a good little You Tube video that shows the difference in the product shown below.

Thetford Aqua Soft Toilet Tissue - 6 Pack

Thetford Aqua Soft Toilet Tissue - 6 Pack

33 In Stock Now.

If you do use normal paper, like I have in the past, keep the cassette level while taking it to a disposal point. This will keep the mechanism clear.

Cassette Tank Cleaner

This is recommended for use at least once a year. It easily removes stubborn calcium deposits that can form on the inside of the waste tank or cassette. It is easy to use and scrubbing is not required.

Thetford Duo Tank Cleaner Concentrate -  800ml

Thetford Duo Tank Cleaner Concentrate - 800ml

17 In Stock Now.

To view our full range of toilet chemicals click below

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  • comment-avatar


    Why did you only get 4 stars when this information is priceless for people that wan't to do the right thing. Sure it helps your business but it also helps the invierment. Very well writen.

  • comment-avatar


    Found this very helpful as we are new to all this, toilets & what one should use to eliminate odours & at the same time being kind to the environment. Thank you for such a helpful article.

  • comment-avatar


    I found the info very helpful , i will be trying the coles ultra boost , thou the only trouble i have been having is the smell of the actual chemicals put in the waste tank, they smell stronger than what else goes in, which is only urine.

  • comment-avatar


    Great site very informative and more importantly unbiased!!! and the online parts system works a treat.

  • comment-avatar


    Great information. Well written.Thanks

  • comment-avatar


    Excellent information just what we needed thank

  • comment-avatar


    What’s the best way to remove the idiots from a smelly cassette? We accidentally forgot to empty it and have cleaned it out a few times but the smell is still obvious. I’m thinking Flush it out with Hot water and disinfectant to kill any bacterial growth.

  • comment-avatar


    *odours* Not idiots!!

  • comment-avatar


    Great advice. Been using laundry soakers for years. Cap full of eucalyptus water soluble solution gives a nice smell. All available from supermarkets. Cheaper the brand the better. Coles own brand is our favourite. We use therfords top tank chemical in our own spray bottle to rinse and keep seal working well. (About 20 parts water to 1 part pink chemical).

  • comment-avatar

    John Feruglio

    My advice is the product that does 3 things, disinfects, deodourisers & cleans no other product is used, more important is where can you discharge such product, the more systems you can put it in the safer the product is! If one product can do all then the cost should be much cheaper than 3-4 products. You must use a disinfectant around the seat, remember a rinse is a rinse & is not a disinfectant. John

  • comment-avatar


    Very informative Thankyou

  • comment-avatar


    Have been caravanning for a few years now. Found a lot of useful information that I was unaware of.

  • comment-avatar


    great advice in an easy to understand language

  • comment-avatar

    Great forum 🙂 Wondering how much “Laundry Soaker” to use to start up the process in our caravan toilet please

  • comment-avatar


    Thank you, this information was very helpful.

  • comment-avatar


    How to stop rubber seal from distortion when using cleaning

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