How to Identify a Toilet Model

To identify a toilet model, find the brand on the porcelain, then look for a stamped, molded, or labeled model number inside the tank. Photograph every marking and note its location, because a tank number, bowl number, and tank-lid part number may identify different things. You can usually gather the information you need without disconnecting the toilet or removing any plumbing parts.

What the Numbers on a Toilet Mean

The most reliable parts lookup starts with the toilet’s construction and all of its component codes, not a tank number alone.

A toilet may have a collection name, a complete-product model number, separate tank and bowl model numbers, and a serial number. Its replacement parts can carry still more numbers.

That matters because toilets that look alike may use different flush valves, gaskets, lids, or other parts. Even toilets within the same collection can have different versions.

The goal is to connect a readable code to the correct component, then match it to the manufacturer’s product information or parts diagram. Shape and photographs help confirm that match, but they should not be your only evidence.

How to Identify Your Toilet Model

Gather a flashlight, a phone camera, a soft cloth, and a towel to protect the tank lid. A small mirror can help with markings that face the wall.

Use the toilet’s construction to choose where to begin.

Toilet Design or Setup	How to Recognize It	Where to Start
Two-piece toilet	A separate tank is attached to the bowl	Inside the tank, then accessible bowl markings
One-piece toilet	The tank and bowl form one continuous porcelain fixture	Inside the tank
Concealed-tank toilet	The tank is hidden behind a wall or inside cabinetry	Exposed bowl markings and any readily accessible tank identification
Intelligent or integrated bidet toilet	Electronic controls or bidet functions are built into the fixture	Accessible exterior model and serial-number labels

Step 1: Find the Toilet Brand

1. Look for a name or logo on the porcelain. Check around the bowl’s rear edge, near the seat hinges, and on the front or sides of the tank.
2. Photograph the whole toilet from the front and side. Include the tank profile, flush handle or buttons, bowl shape, and base.
3. Record the brand exactly as shown. Do not assume that the name on the seat or an internal valve is the toilet manufacturer.

A replacement seat may be from a different company. Likewise, a marking inside the tank can identify a component rather than the toilet itself.

If there is no visible brand, continue collecting codes. A clear stamp and a full-fixture photograph can still give manufacturer support or a plumbing-parts supplier enough information to help.

Step 2: Inspect the Tank and Lid

1. Lift a freely removable tank lid with both hands. Set it flat on a towel on the floor, out of the walking path. Porcelain lids are heavy and chip easily.
2. Stop if the lid resists lifting or remains attached to buttons or cables. Leave it in place rather than pulling on the mechanism; use accessible markings and manufacturer support instead.
3. Shine a flashlight inside the tank. Inspect the back and side walls for ink stamps, molded numbers, stickers, or labels. Photograph the markings before trying to interpret them.
4. Inspect the underside of the lid. Record its markings separately from those inside the tank.

You normally do not need to shut off the water or drain the tank just to inspect visible markings.

On TOTO toilets, look for a black-ink stamp beginning with ST or CST beneath the lid, including older formats with a three-digit base code. Also inspect the back or right-hand wall inside the porcelain tank. Copy the entire string, including any letters after the digits.

Use your camera’s zoom to examine a photograph rather than leaning hard against the tank. A flashlight held at an angle can make raised or recessed characters easier to distinguish.

Step 3: Separate Model Numbers From Other Codes

1. Label each code by where you found it. Notes such as “inside tank,” “underside of lid,” and “rear bowl label” prevent confusion during a parts search.
2. Identify component-specific numbers. For a KOHLER one-piece toilet, the model number inside the tank is the primary toilet model number. On a KOHLER two-piece toilet, that number identifies the tank; the bowl has its own model number, molded into the china on the underside of the bowl flange.
3. Check whether a long code is a serial number. KOHLER and STERLING serial numbers are usually 8 to 11 characters long, most commonly 9 characters. The length varies by product, so confirm the exact code on the serial-number label rather than classifying it by length alone.
4. Keep color and production information, but identify it separately. TOTO color markings use a # followed by a two-digit color code. Retain that code when matching visible replacement parts.

Do not lift or unbolt the toilet to expose a bowl marking. Use a phone or mirror only where you can reach comfortably; an inaccessible number can be investigated through manufacturer support.

A number molded into the tank lid may be a lid part number, not the toilet model. It can still help identify the toilet, especially when the tank stamp is unreadable, but a replacement lid may not be original to the fixture.

Other markings can include:

• A manufacturing date or production code.
• A flush-volume rating in gallons per flush, abbreviated GPF.
• Certification marks.
• Part numbers on the fill valve, flush valve, or other internal hardware.

Keep photographs of these details for later comparison.

Step 4: Replace the Lid and Save Your Record

1. Remove the cloth, flashlight, or anything else you placed near the tank opening.
2. Lower the lid carefully into its original position. Make sure it rests evenly without trapping anything beneath it.
3. Save the photos with your written codes. Include the brand, each code’s location, and the part you are trying to replace.

For an ordinary loose-lid inspection, no plumbing has been disconnected and no refill procedure is needed. Leave any attached lid, concealed mechanism, or electrical enclosure undisturbed.

Saving this information now prevents another search the next time the toilet needs a part.

Step 5: Look Up the Complete Code

1. Search the manufacturer’s name together with the complete code. Add words such as “toilet parts,” “parts diagram,” or “specification sheet” to narrow the results.
2. Prefer the manufacturer’s product page, illustrated parts list, or archived documentation. Match the exact letters and suffixes, not just the first digits.
3. Compare the drawing with your toilet and its original components. Check the tank profile, flush-control position, bowl shape, and flushing mechanism.
4. If the match remains uncertain, send the manufacturer your photos and location-labeled codes. Ask which toilet or component each number identifies and which parts listing applies.

TOTO model suffixes deserve particular care. Some TOTO one-piece model codes begin with MS followed by six digits; in older code families using the 113 and 114 endings, 113 identifies a round-bowl configuration and 114 an elongated configuration. Keep any letters that follow those digits too, because this pattern is not a universal decoding rule for every TOTO generation.

Similarly, on older TOTO two-piece families that use an S suffix to distinguish a standard version from an Eco version, that letter matters when selecting flush-system parts. Use the full model and the tank’s marked flush volume rather than classifying the toilet from its bowl shape.

If an exact search returns nothing, try the base code while preserving the complete original in your notes. Search results with similar numbers are leads, not confirmation.

When Toilet Markings Are Missing or Hard to Read

Faint Stamps, Residue, and Tank Liners

Mineral deposits and residue can hide an otherwise usable model number.

For a freely removable lid, lift it off and place it flat on a towel. Gently wipe the marked area with a soft, damp cloth, then photograph it with light coming from different angles. Avoid abrasive scraping, which can damage a faint ink stamp. Replace the lid securely when finished.

Do not peel away an insulated tank liner to expose a number. Some KOHLER tanks have an Insuliner covering the model marking; the lid’s part number can help KOHLER customer support investigate the model instead.

If a character remains unclear, record it as uncertain rather than silently guessing. A photograph lets a support representative distinguish possibilities such as a letter O and a zero.

Concealed Tanks and Intelligent Toilets

A concealed tank and the visible bowl may have different manufacturers or separate model identities. Identify the component you need to repair: a bowl marking may not identify the hidden flushing mechanism.

Check exposed labels and any cabinet opening that already provides access. Do not remove wall finishes, detach the bowl, or force a flush plate solely to search for a number. If identification requires opening the wall or disconnecting plumbing, use a plumber.

For intelligent toilets, an accessible serial number may be more useful than a molded porcelain code. KOHLER serial-number locations vary by model and can include the back of the fixture, the back of a lid, or behind an access panel. Start with exterior labels and send the serial number to the manufacturer; leave electrical enclosures and connected components closed.

Older or Discontinued Toilets

An old toilet may no longer appear in the manufacturer’s current catalog. Look for archived parts diagrams, installation documents, or discontinued-product listings using the brand and exact code.

Original receipts, installation paperwork, or property-maintenance records can also help. For renters, the landlord or maintenance team may already have the model and approved replacement-part information.

When a model has been discontinued, separate identification from availability: finding the correct model does not guarantee that a replacement tank or lid is still made. Before ordering old stock or a used porcelain component, have the seller confirm the exact compatible model, not merely the collection name or appearance.

If you cannot establish a match, send the manufacturer or a specialist parts supplier your code photos, overall toilet photos, and the name of the part needed.

How to Confirm a Toilet Model Before Buying Parts

Before ordering, verify these points:

• Correct component: Confirm that the identified part is the one you need.
• Correct version: The parts listing matches the full model suffix and any stated production revision.
• Correct flushing mechanism: The listed component matches the mechanism installed in the toilet.
• Correct tank-and-bowl pairing: A replacement porcelain component is explicitly compatible with the other half.
• Correct finish: Visible parts match the manufacturer’s color designation where one is available.

A “universal” description does not eliminate compatibility checks. An aftermarket fill valve or flapper still needs to suit the toilet’s design and flushing requirements.

For a seat, confirm the actual bowl shape and dimensions as well as any model information. Measure from the centerline of the mounting holes to the front edge of the bowl, the bowl’s width, and the spacing between the mounting holes. Unusual shapes and proprietary mounting systems need particular attention.

For a WaterSense-labeled toilet, the EPA’s WaterSense toilet search offers an additional cross-check. WaterSense certification applies to the listed tank-and-bowl combination, not an arbitrary pairing of separately labeled components.

The EPA database may use wildcard characters such as *, #, and X to represent model attributes, including color or finish. Searching the numeric portion of a model code can work better than entering the entire marking. The database is not a universal toilet registry, so an absent listing does not establish that your identification is wrong.

Once the documentation and fixture agree, save the parts diagram alongside your photographs and order the exact compatible part. If they disagree, ask the manufacturer to resolve the mismatch before you buy.

Frequently Asked Questions

How Do I Identify an Ideal Standard Toilet?

Look for codes on the bowl and tank. If the tank is concealed, identify its manufacturer separately rather than assuming the bowl’s model covers the flushing mechanism. Those markings may identify separate tank and bowl components.

Is There a Free Toilet Model Number Lookup in the UK?

Many manufacturers provide free online product catalogs and spare-parts diagrams, but there is no single comprehensive lookup covering every UK toilet. Search by the brand and exact component code. For a concealed-tank installation, you may need separate searches for the bowl and tank.

What Toilet Is Tank Number 10791?

A number alone may identify a component rather than a complete toilet. The brand and the marking’s location matter: a number inside the tank may identify the tank, while a number beneath the lid may identify only the lid. Provide both details and a photograph when requesting a match.

What Toilet Has the Code 48-05-0448?

Use the brand and location where a code appears to help determine whether it identifies a tank, bowl, or other component. It could identify a component or be another production marking rather than the complete toilet. Use a clear photograph of the code and any porcelain logo to request identification before ordering parts.

What Is the Most Common Toilet Model?

There is no single model you can safely assume you have based on how familiar the toilet looks. Similar-looking fixtures can use different tank-and-bowl combinations and replacement parts. A stamped code and a matching manufacturer’s parts diagram are more useful than a model’s popularity.