Century chemical toilet porta potty (C) Daniel Friedman Chemical Toilets - How to Use & Maintain a Chemical Toilet or "Porta Potty"
- 8 Steps to successful use of a portapotty

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A buyer's & user's guide to portable chemical toilets: This article describes use of chemical toilets, how they work, and how they reduce wastewater consumption.

The photograph at page top is of the Thetford PortaPotti, a portable toilet which uses chemicals. Other common portable toilets include models from Sears, the Coleman, and Reliance toilets who provide a hassock model portable chemical toilet.

This article provides the details of the set-up, use, maintenance, cleaning,and emptying-out of chemical toilets. We also discuss portable toilet repairs and winterizing.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Guide to Buying & using a Chemical Toilet or Portable Toilet

Accordian valve flusher on porta potty © D Friedman at Chemical Toilets: use a chemically treated reservoir located directly below the toilet seat. The chemicals reduce odors and perform partial (incomplete) disinfection of the waste.

[Click to enlarge any image]

Article Contents

Chemical toilets have limited storage capacity and must be pumped and periodically cleaned by a septic company.

Similar to simple chemical toilets but more sophisticated in design are recirculating toilets which separate the waste from the chemical and then re circulated the fluid through the toilet tank.

Chemical toilets with larger waste reservoirs are used in RV's and campers as well as for full-sized portable toilets or Porta-Johns used at construction sites and at outdoor festivals.

Readers should also see ALTERNATIVE & WATERLESS TOILETS for a discussion of camping toilets, chemical toilets, emergency-use toilets, waterless toilets, graywater systems, composting toilets, home health care toilets, incinerating toilets, outhouses, and latrines. Citation of this article by reference to this website and brief quotation for the sole purpose of review are permitted.

The following is from: New York State Appendix 75-A.10 Other systems [Web article]

(i) Chemical toilets provide a toilet seat located directly above a vault containing a chemical to disinfect and remove odors from the wastewater. Recirculating toilets use chemicals as the toilet flush fluid. The wastes are separated from the fluid, wastes discharged to an internal holding tank, and the fluid reused.

(ii) The liquids used in these types of toilets do not completely disinfect the wastes; therefore, waste products from these units shall not be discharged to surface waters or to the ground surface.

(iii) The reduced volume wastewater from recirculating toilets may be discharged to a larger holding tank but not to a subsurface absorption system.

Toilet Tips: How to Use and Maintain a Chemical Toilet

Thetford PortaPotti chemical toiletChemical Toilets: use a chemically treated reservoir located directly below the toilet seat. The chemicals reduce odors and perform partial (incomplete) disinfection of the waste.

Chemical toilets have limited storage capacity and must be emptied and cleaned by the user.

The photograph at page top is of the Century 6205 2.6-Gallon Portable Toilet by Century Tool, a portable toilet which uses chemicals to deodorize and disinfect toilet waste.

We built the wooden platform shown underneath this toilet in order to raise the seat height to a more comfortable position, but in normal use this toilet works just fine placed directly on a floor or on the ground outdoors.

Version I of our wooden chemical toilet height platform is shown at the top of this page.

Version II of our chemical toilet height increase platform that added railings and a wider platform for greater stability is shown just below - we call this version, constructed in 2014 the Throne.

Wood platform provides handicapped accessible height and railings for a chemical toilet - The Throne (C) Daniel Friedman Jennifer ChurchThe Throne uses a Thetford® Porta Potty replacing the slightly smaller original Coleman® unit and converting the accordian flush valve to a pump style flush valve.

Designed by Jennifer Church and constructed by the author, the Throne added a 3-inch bottom platform that raised the seat height of the porta-potty to about 19" from the floor. That's the maximum height recommended by the ADA though some users may prefer 20".

If you need to provide seat height and grabrails that meet ADA specifications for accessible designs see

Other common portable toilets include models from Thetford®, Sears®, the Coleman®, and Reliance® toilets who provide a hassock model portable chemical toilet.

How to Operate a Chemical Toilet or Porta Potty

Here are complete details for operation and maintenance of the chemical porta-potty toilet.

Before First Use of the Toilet

  1. Check for deodorant/disinfectant: pull out the “T” handle located at the center of the toilet front to open the sliding door that separates the toilet bowl from the waste reservoir and look into the toilet base.

    If you see blue-green powder or liquid on the toilet bottom and perhaps a tiny amount of water then the toilet is ready for use.

    If there is no chemical visible in the toilet base the follow step 2.

    Otherwise go to step 3.
  2. Add deodorant/disinfectant: locate the chemical toilet disinfectant/deodorant chemicals. Both dry powder and liquid versions of chemical toilet holding tank deodorants and cleaners are available, as we show below where our photographs illustrate Coleman toilet holding tank chemical and Thetford's AquaKem toilet tank deodorant and sanitizer.

How to add chemical deodorant / disinfectant to a chemical toilet

Portable toilet disinfectant by Coleman (C) Daniel Friedman Portable toilet disinfectant by AquaChem (C) Daniel Friedman
  1. Separate the toilet top and bottom sections by un-latching the white plastic clips on the left and right side of the toilet, then lift the top away from the bottom section and set it aside.
  2. Open the waste reservoir: Pull the “T” handle located at the center of the front of the toilet base (same handle as described in step 1 above) to open the sliding door that opens the waste reservoir in the toilet base.
  3. Add chemical disinfectant (see HOW MUCH CHEMICAL to ADD below).
  4. Replace the toilet top half onto the bottom reservoir base and re-latch the two side clips that secure these parts together.
  5. Add water: Push the toilet flushing rubber accordion-valve on the rear left corner of the toilet once or twice to flush water from the toilet top water tank into the toilet bowl. If there is no clean water in the toile top flush reservoir, see HOW to ADD WATER to the toilet top flush tank below).
  6. Close the waste reservoir opening by pushing the “T” handle back in.

The portable chemical toilet is now ready to use.

How much toilet disinfectant / deodorizing chemical to add

One packet of dry powder, or one plastic bottle of liquid portable toilet disinfectant / deodorant (shown above) is sufficient to treat forty gallons of wastewater, but this toilet base only holds about three gallons of waste, so just use a tiny amount, about 1/10 of a dry powder packet or 1/10 of a liquid bottle of chemical. Just estimate – precision is not necessary

Watch out: Keep toilet and RV waste tank treatment chemicals away from children.

How to Use a Chemical Toilet or Porta Potty or Camping ToiletPortable toilet flush lever (C) Daniel Friedman

  1. Have a Seat. Please use this toilet only from the sitting position. Standing means messy splashes.
  2. Toilet tissue: we prefer to use RV-type biodegradable toilet tissue, but because this toilet is to be emptied into a septic system, any kind of toilet tissue is acceptable.

    See TOILET TISSUE TEST for an ongoing test of the break-down of several types of toilet paper including RV-type toilet paper recommended for chemical toilets and RV/Marine sewage holding tanks.
  3. Flushing the toilet after use:
    1. Open the waste reservoir in the toilet base - Pull the “T” handle located at the center of the front of the toilet base (same handle as described in step 1 above) to open the sliding door that opens the waste reservoir in the toilet base.
    2. Flush: Push the toilet flushing rubber accordion-valve on the rear left corner of the toilet once or twice to flush water from the toilet top water tank into the toilet bowl. (see “How to add water to the toilet top flush tank” below). One or two pushes of the valve are usually sufficient. More is ok but you will need to empty the waste reservoir sooner if excessive flush water is used.
    3. Close the waste reservoir – push the “T” handle back in.

How to Add Water to the Chemical Toilet Top Flush Tank

  1. If the toilet top flush water reservoir needs water
    1. Separate the toilet top and bottom sections by un-latching the white plastic clips on the left and right side of the toilet, then lift the top away from the bottom section.
    2. Carry the toilet top section to a convenient location close to a garden hose.
    3. Unscrew the white plastic cap on the top right corner of the toilet top section and fill the tank about ¾ full with clean water. Precision is not necessary, just estimate. Filling the tank completely is ok but makes it a bit heavier for some folks to carry.
    4. Replace the white plastic cap on the toilet reservoir tank.
    5. Replace the toilet top half onto the bottom reservoir base and re-latch the two side clips that secure these parts together.

When to Empty and Clean the Chemical Toilet

Chemcial toilet instructions (C) Daniel FriedmanWhen you observe that the toilet bottom waste reservoir tank is getting full (liquid is near the top of the opening visible when you pull the “T” handle out to give view into the bottom tank) the toilet needs to be emptied.


When use of  the toilet is not going to be required for a few days or longer periods it should be emptied, cleaned, and left empty.

The illustration at left shows simple pictorial instructions provided by Century Tool, the manufacturer of the portable toilet used to illustrate this article.

  1. Adding toilet deodorant / disinfectant through the toilet waste reservoir base opening.
  2. Do not pour toilet chemicals directly into the toilet bowl.
  3. Pump water from the toilet top section flush reservoir into the toilet bowl
  4. Pull the "T" lever to empty water or waste into the toilet bottom reservoir, (then push this opening closed again).
  5. How to un-latch and separate the toilet top and bottom sections
  6. Carrying the portable toilet waste reservoir to a dumping station

How to Empty and Clean the Chemical Toilet

Emptying the portable toilet waste reservoir into a toilet or other dumping locadtion

  1. To empty out the portable toilet:
    1. Separate the toilet top and bottom sections if you have not already done so.
    2. Empty the toilet waste reservoir by unscrewing the large round cap found on the rear of the toilet waste reservoir. You’ll notice that when carrying the toilet waste reservoir by its handle this cap will be “up” and the “T” handle or toilet front will be facing down.
    3. Be sure that the toilet bottom reservoir is closed: that is, assure that the “T” handle at the toilet front has been pushed in.
    4. Carry the toilet outside: For convenience the entire toilet can be carried outside, or if you prefer, separate the top and bottom sections of the toilet while it is still indoors, and then each half can be carried separately outside. Handles on the rear of both top and bottom halves of the toilet allow easy carrying.
  1. Wash the toilet top and bottom halves thoroughly outdoors using a garden hose. If a small amount of deodorant/disinfectant remains in the waste reservoir you can add water from a garden hose, slosh the waste inside the reservoir to loosen it, and then empty this diluted wastewater out.

    Now you are ready to install a new dose of chemical toilet deodorant and a few ounces of clean water.

Where to Empty a Chemical Toilet or "porta potty"

If a local septic tank outdoor access port is available, open the septic tank pump-out port at the top of the septic tank cleaning riser pipe. Pour the toilet waste reservoir contents into that opening and replace the cap on the pumping port immediately.

If the septic tank pump-out port has become buried by deep snow, or if no septic tank outdoor port nor RV dumping station is available, the portable toilet can be emptied into an indoor toilet – pour carefully so as not to splash.

Is it acceptable to ever dump an RV toilet into a home septic system tank?

Chemical toilet being emptied into a septic tank (C) Daniel FriedmanThe answer is, ... it depends.

Our photo (left) shows a small chemical toilet holding tank being emptied into the service riser over a residential septic tank. In some circumstances this is ok.

RV HOLDING TANK DUMP INTO SEPTIC TANK? is a detailed article explaining when it is probably ok and when it is probably not ok to dump a chemical toilet, a porta-potty, or an RV waste holding tank into a septic tank (rather than dumping these at a sanitary waste disposal station, for example, at a campground or marina).

Portable toilets include these brands: Thetford Porta Potti, SeaLand’s SaniPottie, Coleman Portable Toilet, Fiamma Bi-Pots, Century Portable Toilet, Dometic Sani Porti, Visa Potty, Companion Eziloo and Primus Deluxe Portable Loo. CONTACT us to add other portable or camping or alternative toilets and products.

Also see our detailed article about camping and emergency use toilets found at CAMPING & EMERGENCY USE TOILETS

Watch out: SEPTIC & CESSPOOL SAFETY discusses the importance of safe, non-collapsing and child-proof septic tank access covers.

How to Store a Chemical Toilet When Not in Use

When use of the chemical toilet is not going to be required for a few days or longer periods it should be emptied completely, washed, and left empty.

For odor and sanitation control, add a fresh dose of disinfectant/deodorant to the toilet waste reservoir followed by about a half-cup of water (just enough to wet the dry chemical and cover the bottom of the waste reservoir).

See How Much Chemical to Add above

Do not leave the toilet top tank filled with flush-water as it may freeze and damage the toilet.

Replacing the Accordion Valve on a Chemical Toilet or Porta Potty

Question: How can I replace the accordion valve flush-plunger on my chemical toilet?

Accordian valve flusher on porta potty © D Friedman at The accordian valve on my chemical toilet is damaged. Can it be replaced? - B. Howard

Reply: Yes but it's not easy to replace the accord ian valve or flush valve on a porta potty

The accordion valve on a chemical toilet is that flexible plunger pushed to force water from the reservoir tank into the toilet bowl (photo at left).

On at least some chemical toilets it's a replaceable part - you'll want to obtain exactly the proper part that matches your toilet to be sure that the replacement fits and doesn't leak.

I've replaced similar parts by carefully cutting and pulling away the old accord ian valve without damaging the plastic that surrounds the valve mounting opening. The new valve may need to be warmed in hot water a bit as well as kept wet to fit it into the opening. But I found it was a difficult process.

Watch out: You'll probably find, as I did, that a sticky sealant is used between the accordion valve or flush valve surface and the upper surface of the plastic porta potty at the mounting hole.

You may need a replacement sticky gasket kit from the manufacturer to do this job reliably. If you fail to seal the valve at its mount position the new toilet flush valve will look fine, but it may not pump an adequate dose of water into the toilet bowl for flushing.

Preparing a Chemical Toilet Porta Potty for Use in Freezing Conditions

Question: How to freeze-proof a porta potty

I want to keep my porta potty in my van for occasional use during the upcoming Michigan winter. How do I keep it useful without it freezing? - Bonnie Jones

Reply: RV Wastewater System Anti-Freeze, Heat, or Leave the System Empty

Short answer: to keep a portapotty in a van in freezing conditions, first buy and use RV wastewater and flush water environmentally safe antifreeze product from an RV supplier.

Option 1: leave the toilet drained, empty, and treated

We leave a chemical toilet in a remote cabin in northern Minnesota through very deep freezing weather.

But first we empty the water from the flush reservoir and we empty the toilet base as well. Then we leave a very small quantity of water along with toilet treatment chemical in the toilet base receptacle.

By that means the toilet fresh, without a lingering worry about developed odors, bacteria, or mold growth while it's sitting idle. The toilet is almost ready to use when people return to the cabin. All that's needed is to add water to the flush reservoir.

I would not leave any water in the toilet nor waste in the toilet in freezing conditions. The risk is that frozen water or wastewater breaks the toilet and later thaws, leaving a mess in your van.

Option 2: use an RV antifreeze product in the chemical toilet?

For buildings (or vans) where we need to leave a portapotty in ready-to-use condition in freezing conditions we'd have to add a heat source OR we'd need to add an antifreeze mix to be sure of avoiding damage. You MIGHT get away with letting a small amount of waste in the toilet bottom freeze but it's risky.

People who own an RV or a boat that includes water supply and waste piping learn that to winterize their vehicle they need to drain the system of water and usually they also add an antifreeze to be sure that pumps or any components that might contain residual water won't be damaged by freezing.

If you check with your local RV suppliers you'll find that they sell RV wastewater holding tank antifreeze for use in the holding tanks in those larger vehicles. Most RV and Marine antifreeze solutions use ethylene glycol (EG) or propylene glycol (PG), with glycerin as a primary second ingredien

t. Also in RV applications and some others, antifreeze solutions include phosphates as an anti-corrosion agent that you would not need in an all-plastic water or wastewater system. (Phosphate-containing antifreeze is used in the U.S. but prohibited in Europe.)

According to Splashproducts propylene glycol antifreeze is considered "generally regarded as safe" or "GRAS" by the U.S. FDA. The company states that their RV & Marine antifreeze is "Safe for incidental contact with people, pets, and wildlife". [1]

We'd always prefer to use an environmentally safe product that can be used in both the flush water supply and in the wastewater holding tank if you are going to use an antifreeze in a chemical toilet or portapotty.

You will also find "drinkable" antifreeze (propylene glycol based antifreeze) sold by other RV suppliers and intended for use in the RV's drinking water holding tank and pump. Although no one is going to be drinking out of your porta-potty, that's what I'd prefer to use in the porta potty flush reservoir tank.

Watch out: be sure to follow the proper dilution instructions on the product label so that you don't over-dose your porta potty nor the dumping station into which it is later emptied.

Watch out: many antifreeze solutions are toxic if ingested (drunk) and may also be environmental contaminants that should not be dumped into a septic tank nor onto the ground surface.

Are chemical toilets useful as a septic system design alternative or not?

Thetford PortaPotti chemical toiletWhile at least some manufacturers of the chemicals used in chemical toilets (to deodorize and to stop bacterial action in order to prevent dangerous production of potentially explosive methane gas inside the toilet) inform us that their products are environmentally friendly, New York State, as an example, does not want homeowners discharging chemical toilets into the environment.

Further, as we have advised at RV HOLDING TANK DUMP INTO SEPTIC TANK? about dumping RV toilets into the septic system, there is some risk that discharging these chemicals into a conventional septic system could cause it to stop working, depending on the frequency and volume of chemical waste to be disposed-of.

With this in mind, we use chemical toilets where there is no onsite waste disposal system at all such as in a weekend cabin without plumbing, or in RV's, but not as a permanent toilet facility in a permanently occupied building.

Chemical toilets or camping toilets and porta-potties are also suitable for the "pack it in, pack it out" environment in which waste is removed from the site and dumped at an approved RV dumping facility.

Chemical or portable toilets may also be a life-saver for home health care or for elderly, disabled, or other people of limited mobility who need a close-by toilet or who need to avoid excreting large amounts of drugs or antibiotics into a private septic system.

See DISABLED or ELDERLY-USE TOILETS for more information.


Continue reading at ALTERNATIVE & WATERLESS TOILETS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see CHEMICAL TOILET FAQs - questions & answers posted originally at the end of this page.







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