Dometic 300
300 Series, white standard-height gravity toilet with polypropylene bowl
View matching productDometic 300, 310 & 320 RV Toilets: Photos, Fit & Parts Guide
Replacing an RV toilet or servicing its flush parts starts with identifying the exact Dometic model. The 300, 310 and 320 are all foot-pedal gravity-flush toilets, but their bowls, seats, depths and required clearances are different. Their low-profile counterparts are numbered 301, 311 and 321. Compare your toilet's model label—located on the base below the water valve—with these manufacturer dimensions before ordering.
Identify your 300, 310 or 320 toilet
These photographs show complete Dometic standard-height gravity-flush models. Compare the model label beneath the water valve, the bowl style and the installation dimensions below.
Dometic 310
Standard-height round ceramic-bowl RV toilet, white. Product 302310081.
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Dometic 320
320 Series, bone standard-height gravity toilet with ceramic bowl
View matching productSee the model-specific numbered parts references: Dometic 300, Dometic 310 and Dometic 320.
Frequently replaced components
Use these photographs to recognize the original part. Confirm the exact manufacturer number in your toilet's illustrated guide; parts that look similar are not necessarily interchangeable.
Water valve · 385311641
Fresh-water valve service kit; confirm the existing valve and model.
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Flush-ball seal · 385311658
Replacement bowl seal; match the original part number and production version.
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385311646
White replacement seat and cover for the compatible 310/311 models
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385230335
Hand-spray vacuum-breaker kit listed for the compatible 310 model
View matching productWhich standard-height model is installed?
| Factory specification | Dometic 300 | Dometic 310 | Dometic 320 |
|---|---|---|---|
| Bowl material | Polypropylene plastic | Vitreous ceramic | Vitreous ceramic |
| Original seat material | Polypropylene plastic | Polypropylene plastic | Enameled wood |
| Overall height | 19¾ in | 20 in | 19¾ in |
| Outside width | 16 in | 15 in | 14¾ in |
| Front-to-back depth | 19¾ in | 19 in | 22 in |
| Seat height | 18¼ in | 18 in | 18¼ in |
| Minimum back-wall rough-in | 8½ in | 10 in | 11 in |
The rough-in is measured from the center of the floor flange to the back wall. The 320's longer bowl requires more front-to-back room than the 310; neither model should be chosen from seat height alone. Each must discharge directly to a suitable RV holding tank, not through a conventional horizontal residential drain.
Use the original manufacturer part numbers
Dometic's numbered 310/320 service sheets distinguish a flush-ball seal, water valve, vacuum breaker, seat assembly and floor-mounting hardware. Similar-looking replacement parts are not necessarily interchangeable across every model or production revision.
| Manufacturer part | Factory part name | Model reference and selection |
|---|---|---|
| 385311641 | Water valve kit | Identified on Dometic's original 310/320 numbered parts drawings; check the model and original valve |
| 385311658 | Flush-ball seal | Identified on the 310 and 320 numbered parts drawings |
| 385311646 | White seat and cover | 310 seat style, also listed for compatible 311 low-profile toilets |
| 385311647 | Bone seat and cover | 310-type seat design; do not substitute for the longer 320 seat without matching the original number |
| 385311863 / 385311864 | 320 replacement seat and cover, white / bone | 320-specific seat parts listed separately from the 310 seats |
| 385230335 | Hand-spray vacuum-breaker kit | Manufacturer's 310 drawing identifies this as a vacuum breaker with optional hand-spray arrangement |
| 385311652 / 385311653 | Floor mounting hardware and seal, white / bone | Refer to the specific model and included components before replacing the floor seal |
Seat and hinge
At the top of the ceramic or plastic bowl; model-specific size and mounting hardware.
Flush-ball seal
At the bottom of the bowl around the moving flush ball; maintains water in the bowl.
Water valve and vacuum breaker
At the toilet's side/rear water supply connections; different parts with different functions.
Floor flange seal and fasteners
Between the toilet base and the RV's approved floor flange.
Original functional identification reference, not an exploded mechanical drawing. The factory manuals linked below contain numbered diagrams.
When repairing instead of replacing
If the bowl will not hold water, check for debris or damage at the flush-ball seal and follow Dometic's seal-service procedure. Water leaking near the supply fitting calls for inspection of the water valve and its connections. A leak at the floor or a loose toilet requires examination of the mounting hardware and flange seal rather than automatically replacing the flush-ball seal.
On 310 and 320 ceramic-bowl models, Dometic specifies that the factory-sealed ceramic bowl should not be separated from its plastic base for normal servicing. Turn off and disconnect the fresh-water supply before removing any valve or hose, and follow the toilet manufacturer's winterizing procedure to prevent freeze damage.
Original illustrated manuals
Dometic 300/310/320 installation manual and dimensions (PDF), Dometic 310/320 component positions and service instructions (PDF) and Dometic numbered replacement-parts guide (PDF). These open separately on mobile for a closer view of factory callouts.
For a removable toilet with a self-contained waste tank instead of a fixed floor flange, see the Dometic 972/976 portable toilet guide.
Need a shorter toilet? Compare the Dometic 301, 311 and 321 low-profile toilet models by bowl material, seat height, rough-in and model-specific parts guides.
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