How to Add a RV Cassette Toilet & Shower

Written by john cagney nash
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How to Add a RV Cassette Toilet & Shower
A toilet in your RV means no more late-night trips to campground rest rooms. (rv,motorcoach image by Greg Pickens from

A cassette toilet and shower is a self-contained plastic device which looks and functions similarly to the Porta-Johns familiar from sporting events, outdoor concerts and construction sites. The primary difference from the Porta-John is that in a cassette toilet the effluent is held in a slide-out holding tank, or cassette, beneath the toilet. That cassette can be removed for emptying and rinsing through an access door in the outside of the RV, so the waste does not have to be carried through the vehicle. The factory installation of a cassette toilet and shower will add in the region of £650 to its purchase price, but the adding of one as a do-it-yourself project is a relatively simple project.

Skill level:

Things you need

  • Cassette toilet and shower
  • Sealant
  • Household toolkit
  • Circular saw OR
  • Jigsaw

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  1. 1

    Plan the location of your cassette toilet and shower as a trade-off between a comfortable seat height inside the vehicle, and a service hatch location on the outside that is low enough for the filled cassette to be removed without inconvenience. The removable tanks typically hold around five gallons of effluent, so will weigh about 18.1kg. when full.

  2. 2

    Clear an area inside your RV to accommodate the cassette toilet and shower. The location must allow the service port of the cassette, whether to the left or right, to be tight up against an outside wall.

  3. 3

    Follow the installation instructions delivered with your cassette toilet and shower. Typically you will use a manufacturer-provided template to mark a properly sized cut line on the wall where the service hatch is to be located. Before cutting the hole, use a stud locator to ensure there is no preinstalled wiring or pipework, and no support members or hoops, passing through the area. Cut the hole using a circular saw or jigsaw.

  4. 4

    Fix the cassette toilet and shower into position using manufacturer-provided fasteners. Because the new unit is an entirely self-contained unit, there is no plumbing or wiring to be done. If its location is inside a wet shower, seal around all the edges of the new unit using bathroom/kitchen silicone sealant.

  5. 5

    Use the cut-out panel of RV wall to fabricate a hinged door which, when open, allows unobstructed access to the cassette and fresh water fill assemblies of the new toilet. Ensure the door is waterproofed with a rubber seal to keep rain out; a pre-adhesive foam strip sold by home improvement warehouses to cut window drafts will work well. Fit the most convenient type of hasp or lock to the door that will hold it shut when the RV is under way.

Tips and warnings

  • Buy a unit with a 180-degree swivelling seat, which allows fitting to any wall in the RV.
  • Because the cassette toilet and shower has its own fresh water reservoir as well as the effluent holding tank, it must be winterised along with the RV's other systems before winter arrives.

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