Replacing Sealand SC111 With Dometic 310 or 311 in 2008 Fleetwood Southwind

Updated 12/04/2025 | Published 11/09/2025

Products Featured in This Question

Dometic RV Toilet Floor Flange Adapter Kit - 4 Bolt Flange to 2 Bolt Toilet - Bone

(9)

$120.64

Dometic RV Toilet Floor Flange Adapter Kit - 4 Bolt Flange to 2 Bolt Toilet - White

(21)

$119.36

Question:

Hi. We are finally replacing the Sealand SC111 toilet, original equipment in our 2008 Fleetwood Southwind. The Sealand SC111 has a 4 bolt base, so I imagine I’ll need a 2 hole adapter for the 310, or 311? Which brings me to my next question: the 310 is allegedly 20 inches high, with a seat height of 18 inches? Gigantic. Our Sealand SC111, as I see it, is 13 inches tall, with a seat height about an inch less. That toilet does sit on a 6” riser/platform in the bathroom, so I reckon we would need the lower 311? Thanks for any help you can provide. Robert

asked by: Robert L

Expert Reply:

Hey Robert! You will need the Dometic RV Toilet Floor Flange Adapter Kit # DOM73FR to install the Dometic toilet where the Sealand was. As far as the height is concerned, are you happy with the current toilet height? If you want the taller Dometic 310 RV Toilet # DOM57FR, and the space isn't an issue, it is perfectly fine. Otherwise, the 311 # DOM67FR would be a closer match.

The main thing is that you make sure your rough-in measurement is at least 10" for the toilet to fit. Keep in mind, a 4-bolt toilet can throw off this measurement, so if you're not sure, removing the old toilet is the best way to double-check before you order.

expert reply by: Robin H

Rough-In Measurement
(click to enlarge)

Robin H.

12/1/2025

Hey Robert, how did the swap to the Dometic 311 toilet go in your Southwind? Did the floor flange adapter fit smoothly with your existing setup? Your update could make it easier for the next person replacing a Sealand toilet.

Robert L.

12/4/2025

@Robin Hey Robin! To be honest after living for a week with our old leaking Sealand, my wife said ‘nope’ and we hired a local plumber. We live in Mexico, and the day before had driven up to the border to pick it up - and pay tariffs. So the RV bathroom is small, and mostly what I saw was the plumbers backside! He know him to be quite sharp, so we agreed when he said we must also must add a wax ring. And we did, or he did. So far the toilet has been very good. We like it a lot.