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This Dometic RV toilet pairs an elongated porcelain bowl and 18" chair-height seat with a compact 7-5/8" minimum rough-in, giving you full-size comfort in tight RV bathrooms. 360-degree flush and serviceable ball seal simplify everyday use.
Upgrading from a small, low, or round RV toilet can get tricky when your bathroom has limited room behind the flange. The Dometic 420 pairs an elongated porcelain bowl and full-size seat with an 18" seat height while requiring a minimum 7-5/8" rough-in. You get a chair-height, residential-style seating position while keeping the rear space requirement compact for an elongated toilet.
When residue collects around areas that the flush water does not reach, keeping your toilet ready for the next use takes extra attention. The rimless 360-degree PowerFlush sends water around the bowl for full-coverage rinsing, while the smooth porcelain surface makes cleanup easier when something does get left behind. A dual-action foot pedal lets you add water or flush without reaching down, while the easy-clean hinge improves access around the seat. The soft-close seat and lid close gently instead of clattering in close RV quarters.
A worn ball seal can keep your toilet bowl from retaining water and can let tank odors reach the bathroom, making a small service item a major ownership problem. The 420 uses a no-tool replacement ball seal, along with a glass-reinforced, sonic-welded water valve and a one-way valve that helps prevent backflow into the fresh-water supply. When the ball seal wears, you can replace that service component directly instead of treating it as a reason to replace the entire toilet.
A familiar floor connection does not eliminate the need to measure the bathroom around your toilet. The 420 uses a universal two-bolt floor connection and comes with a pre-installed floor flange seal and mounting hardware, but the installation still needs at least a 7-5/8" rough-in and room for its 19" depth, 15" width, elongated bowl, pedal, lid, nearby doors, cabinetry, and your legroom. Check the water-supply location as well, since an existing line may need adjustment if the inlet position differs. If your toilet mounts on a raised platform, factor that into the 18" seat height so the finished seating position isn't taller than you want.
Customer Satisfaction Score:
96% were satisfied with this product
4% of customers were not satisfied
Ratings & Reviews
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Christopher H.
9/17/2026
Thanks for the installation tips and the photo Forrest! Glad this was a simple install.