Mars, Frito-Lay and Reser's fine foods are the top water users ........

 Yes — those three names are the right cluster. The biggest water users in Topeka are the large food-manufacturing plants, because washing, cooking, sanitation, and cooling are extremely water-intensive.

The companies you named

Frito-Lay (PepsiCo)
Plant at 1303 SW 41st Street. One of their larger U.S. snack plants (Lay’s, Fritos, Doritos, Cheetos, Tostitos). They have publicly talked about cutting water use ~52% per pound of product since 1999 through process changes and sanitation practices. They were among the customers who noticed and complained when Kansas River chloride spiked in 2018, which is a sign they use city water in production, not just for restrooms.

Mars Wrigley
Chocolate plant in Kanza Fire Commerce Park (Topeka Blvd / Innovation Parkway area). Opened around 2014, later expanded (Snickers, Milky Way, 3 Musketeers, M&M’s lines). It was built as a LEED Gold facility with explicit water-efficiency targets: ~35% reduction in potable water use versus a baseline building, 71% reduction in water used for sewage, and no irrigation. Still a large process-water user.

Reser’s Fine Foods (“Reesers”)
Salad / refrigerated-foods plants and distribution, including the main salad plant at 3728 SE 6th Street. They have been in Topeka for decades, employ well over 1,000 people locally, and have been expanding warehouse/distribution space. Produce washing, cooking, and sanitation drive the water demand.

Other names that often show up in the same conversation: Hill’s Pet Nutrition (another large manufacturer) and, historically, Goodyear (they also reacted to the 2018 chloride issue). Hospitals and the state complex use a lot of water too, but the food plants are the standout industrial users.

Scale

The City of Topeka Water Treatment Plant averages about 21–22 million gallons per day (roughly 8 billion gallons a year). In public rate presentations this year, city staff used “one of our industrial users at 10 million gallons” as an example — that figure is monthly. A single customer at that level is using on the order of 300,000+ gallons a day. A handful of food plants can therefore account for a noticeable share of total industrial demand.

Topeka still uses a declining-block rate structure: industrial customers (and especially “Industrial II”) pay less per thousand gallons than residential customers. That is why the city talks about large industrial users separately when they discuss rate increases.

Is this public record?

Yes. Municipal water-billing data is generally public under the Kansas Open Records Act. You can request:

• Usage by customer class (residential / commercial / industrial / Industrial II)
• Lists or rankings of the largest volume customers (they sometimes redact exact account names or give ranges)
• Historical industrial usage for planning or rate studies

The city already discusses “our industrial users” in open council and utility meetings, so the existence and approximate size of the big plants is not secret. Individual monthly bills for a named company are more likely to be treated as customer-specific and may be redacted or summarized.

If you want the actual ranking and gallon figures, the practical next step is a KORA request to the City of Topeka Utilities Department asking for the top water customers by volume for the most recent calendar year (or a multi-year average), broken out by customer class. They are used to those requests.