Sierra Vista staff propose major wastewater upgrades and two-year rate increases to cover aging plant work

Sierra Vista — City staff told the City Council on Monday that the city’s wastewater treatment plant needs near‑term repairs and process changes and proposed a two‑year set of rate and fee increases to pay for work.

Bryce Kirkpatrick, the city’s external operations manager, said the plant’s geomembrane liners — installed around 2012 — have an expected life of about 10 years and that one liner failed last summer in an anoxic basin. He described the proposed core work as replacing liners with longer‑lived shotcrete, adding capacity (a third clarifier) and installing disinfection if required by the Arizona Department of Environmental Quality when the plant’s permit is renewed.

Kirkpatrick said the shotcrete option has an estimated useful life of about 20–25 years and was chosen as a mid‑range cost alternative to full concrete liner replacement. “We rely on geomembrane liner basins. These liners have a roughly 10 year expected life and they were installed mostly in 2012,” Kirkpatrick said. He added that the plant’s redundancy is limited, so taking one treatment train offline for maintenance has operational impacts.

City Finance Director David Felix and staff outlined the funding proposal tied to those needs: a 15% increase to sewer rates on July 1, 2025, and another 15% on July 1, 2026; an increase to sewer connection fees (about 2.25 times current levels); and suspension of infrastructure, police and fire connection impact fees so wastewater capacity funding can be prioritized. Felix said the plan is intended to stabilize the sewer enterprise fund and pay anticipated capital costs while the city evaluates financing and phasing options.

The staff presentation listed other recommended work: site grading and curb work around headworks to limit stormwater inflow, piping and electrical upgrades, replacing wetlands treatment with direct contact basins for disinfection/dechlorination routing, and remodeling the plant operations/lab building. Kirkpatrick and council members discussed that wetlands at the plant generate evapotranspiration losses and may be removed to improve recharge efficiency and reduce maintenance.

Costs were described as “multi‑million” and were discussed in ranges during the meeting; city staff said the larger initial conceptual plan had been pared back to critical elements to control cost. Felix told the council the city is targeting the two‑year rate path in part because a current sewer note will be paid off in January 2027, changing debt service timing.

On refuse, staff proposed residential rate increases of 10% on July 1, 2025, and again on July 1, 2026, citing rising vehicle maintenance and parts costs, wage increases and higher capital prices for replacement trucks.

The presentation included estimates of household impact: combined bi‑monthly sewer and refuse bills would rise by roughly $8–$11 on the first increase and by a similar amount in the second year, depending on can size and customer class. Staff emphasized exemptions and discounts would remain available (including an advance‑pay 10% discount and existing low‑income/aid discounts administered through DES).

No final council votes on the plant upgrades or the rate increases were recorded in the meeting transcript; staff described the items as proposals that will return for formal action following public hearings and continued design, financing and grant‑seeking work.

Why it matters: The wastewater plant is an enterprise fund whose failures can trigger regulatory orders, public‑health risk and limits on growth. Staff framed the proposal as addressing near‑term failures (liner replacement and redundancy) while seeking to limit rate shock by phasing increases and exploring financing alternatives. The city also said it would evaluate private‑sector alternatives and phased construction to control costs.

What’s next: Staff said if council moves forward with the proposal the city will hold public hearings and begin a rollout and outreach process; implementation dates in the presentation targeted June 1 for internal rollout steps and July 1 for the first rate change.