Common Dometic 320 Toilet Problems (Leaking or Not Holding)

Dometic may be a good manufacturer, but they don't always hit a home run with their products. Case in point, the 320 toilet. There seems to be a lot of complaint about this model as well as the poor customer service some owners receive. Dometic will strictly stick to the end of the warranty term.

There are at least 5 common problems you will encounter when you have this toilet model in your RV or trailer. One of those common problems will be the leaking of urine and water through the seal on the floor. It may be a design flaw and if you are past your warranty do not expect to get any help.

To learn more about this toilet model and its problems, just continue to read our article. It explores the issue so you have the correct information about these problems and what you can do about them. Dometic may not be of much help in the end.

Common Dometic 320 Toilet Problems


There happen to be several common problems and if you do any research on this topic you may find that while some websites list 5, there may actually be a lot more. Here are some of those common problems:

- Water leakage- this will be dealt with in more detail in an upcoming section. Suffice it to say you have 3 possible sources for this problem. The fixes are quite simple but may be expensive, depending on where you buy the replacement parts.

-Water doesn’t shut off- the source for this problem will be a leaking water valve. The only repair you will have for this issue is to replace the water valve.

- Bad odor- when you start to smell a foul odor, it may be due to a malfunctioning rubber seal. The only fix for this problem will be to replace that rubber seal.

- Water not flowing into the bowl- this is due to a blocked or clogged water screen. You have to clear any debris from the screen to solve this problem.

- Dometic 320 parts are hard to find- it is a Dometic toilet and RV related so parts will be rarely found outside of RV parts and accessories outlets or Dometic. Third-party parts may have quality issues.

Dometic 320 Leaking

This seems to be a very common problem many RV owners encounter. The sources for this issue are: a Faulty flange, a Cracked bowl, or Improper sealing.

To fix these problems you may have to replace the flange or repair the bowl. The latter option may be difficult to do as the bowl seems to be not serviceable. At least according to Dometic

This toilet model is part of the 300 series which is an entry-level toilet model. You are not going to get much help repairing them. Especially when the warranty term ends.

One owner was past the end of his term by 8 months and Dometic would not help him in any way although it was a design flaw. You are going to have to replace the toilet with a better brand or model when you are in this situation.

According to its construction description, the quality of these toilets is very low and very basic in materials and parts.

Dometic 320 Not Holding Water


This is never a good situation to be in. You need that water to flush the waste away. But when the tank or the toilet does not hold water, then you have a couple of problems that need your immediate attention.

The first issue may be the seal. If it is damaged or it was not installed correctly, you either have to wipe the seal down, and re-install it, or replace the seal. The wiping will remove any debris that may be hindering the seal.

But this is not going to be your only source for this problem. If you fixed the seal or it is not the problem, shut the water valve off and look for clogs. If there is a clog, take the appropriate steps to remove it.

You can pour toilet cleaner into the bowl to see if it is clogged or not. Once you have solved this problem, re-test the toilet to make sure those fixes worked. If the problem is not solved, you may have to uninstall and re-install the toilet.

If all of this fails, take it to an RV dealer that handles this problem and can replace the toilet for you.

Dometic 320 Toilet Seat Replacement

This is not going to be a difficult repair or step to take. You will find that Dometic does sell spare parts for many of its appliances on its website. Currently, they offer to replace the seat with a new toilet.

Their 320 models for just the seat and bowl are $419 through their website. Or to save money, you can go to Amazon and get the seat and lid for just over $130. The complete bowl and seat combination at Amazon lists for around $300.

The biggest problem you may have in replacing your current seat would be to find a slow-closing model for your toilet. These seem to be rarer than some Dometic parts.

Then there is a place called the RV Toilet Store and they have the same seat as Amazon but for only a couple of dollars cheaper.

Click here to see what they have in stock.

A quick internet search should bring some results near your current location. Make sure to check out the different RV parts outlets to see what kind of price you can get.

Dometic 320 Water Valve Replacement


These will be as easy to get as the toilet seat. The first place to look would be Dometic’s website. They should have this part in stock and on sale. Or you can go to Amazon and get one for roughly $14.

Other outlets like Camping World and the big box stores like Home Depot, should have some in stock for you. If they do not, then you can always try Walmart. That store is advertising one for $51 approx and it is said to fit the 300 series of toilets made by this company.

Underneath the image for the advertised model, there is another model on sale and it is the same as the one at Amazon but for a dollar less approx. You should have no trouble finding a replacement water valve if that is your toilet’s problem.

Dometic 320 RV Toilet Parts Diagram

What we do know about this toilet is that it is an entry-level model and it comes with few parts. That may make it cheaper and easier to fix when something goes wrong. But that may not always be the case and a good parts diagram will help speed up your repair time.

Here is the diagram for this model of a toilet. The link to the diagram will follow as it has a table labeling all the parts with their part number:


For the list of part names and their part number click here. This exploded diagram should help you find exactly where all the failed parts are located. You should be able to find the parts at that outlet or some other RV parts or supplies outlets in your area.

These other outlets may be cheaper than buying directly from Dometic. Plus, you may get them faster than if you ordered from that company.

Download The Dometic 320 Service Manual


The best place to go will always be the manufacturer. They should have a library of manuals in their database to make sure their customers’ requests are met. Dometic does this and you can find it at this link.

Then, if that link is not helpful, you can always go to our go-to manual outlet. They have a manual for just about every product that has been made today. Just click on this link to get to their option. Be prepared to pay for the download.

A good internet search will provide you with more than just these two websites. If you do not like either, there may be one that offers their download version for free.

Manuals for this toilet model should not be hard to find since the company continues to make the toilet and install them in a variety of RVs.

Some Additional Words

While it would be nice to have a perfect operating toilet in your RV or trailer, it is not going to happen all the time. When problems arise it pays to know the common ones so you can either fix them quickly or eliminate them from being a possible source.

Thankfully, the 320 toilet from Dometic may only have 5 possible common problems. There may be more but these 5 are the most common. This issue seems to have plagued the 300 toilet series Dometic makes.

It is not the best model you can get from the company but it may be the least expensive.

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