How to Identify Your Toilet Type
Not sure if your toilet is a rim jet or a siphon jet? Learn the key differences between gravity-fed toilet types and how to identify your fixture.
Understanding the type of toilet in your home can help with repairs and upgrades. Residential toilets are usually classified into four categories: upflush toilets, pressure-assisted toilets, gravity-fed rim jet toilets, and gravity-fed siphon jet toilets. Knowing which one you have makes troubleshooting easier.
First, you can rule out upflush toilets if your fixture sits above the sewer line and has no external grinder pump. These are typically found in basements or areas below the main drain. You can also rule out pressure-assisted toilets if you do not see a pressure vessel or pump inside the tank. That leaves gravity-fed rim jet and gravity-fed siphon jet toilets.
Question:
How can I tell if my toilet is a gravity-fed rim jet toilet or a gravity-fed siphon jet toilet?
Answer:
If your toilet has two holes at the bottom of the bowl, with one smaller jet hole aimed at the larger outlet, it is a siphon jet toilet. A rim jet toilet relies entirely on water flowing from openings around the rim. Siphon jet toilets create a stronger flush by sending part of the water through the jet hole to help start the siphon action. This design is more common in modern residential toilets.
The siphon jet hole, located just in front of the outlet, directs water quickly into the trapway, boosting the flush. Rim jet models do not include this extra jet at the bottom of the bowl. If you see both the main outlet and a smaller jet hole, you likely have a siphon jet toilet.
For more details, check this Family Handyman guide on toilet types. You can also review this Home Depot toilet buying guide for comparisons.
I’m Chris Mayer, writing for Plumbing 101.
