City Engineer Says State Restrictions Limit Capacity At Lavon's Main Sewer Plant
Lavon's main sewer plant has limited capacity to accept new wastewater because of recent state restrictions, according to a review by the city's consulting engineer.
The Oct. 12 letter reviews plans for Heritage Square, the 110-acre commercial development at SH 78 and SH 205 that includes an approved Walmart site. In it, the engineer wrote that "due to recent flow restrictions placed upon the Bear Creek WWTP by TCEQ, the available capacity to receive sanitary sewer flows is limited," and that "any increase in flow could result in an overcapacity situation at the facility." TCEQ is the Texas Commission on Environmental Quality, the state agency that regulates wastewater.
The letter also says the city "is reexamining the entire sanitary sewer system to determine if there are other options available to help mitigate these TCEQ restrictions."
The City Council is scheduled to vote Tuesday on Heritage Square's final plat and on up to $2.7 million in sales tax incentives for the project. The developer's engineers, meanwhile, have responded to the review with figures of their own.
The Two Sets Of Numbers
According to the city engineer's letter, a new sewer study shows Heritage Square and nearby land would send about 114,000 more gallons a day to the plant than earlier estimates predicted.
The developer's engineering firm, LJA Engineering, says that figure should be about 11,400 gallons a day, ten times less, and asked the city to correct it. In its Oct. 13 response, the firm projected that total flow to the plant would reach about 684,000 gallons a day, which it said "remains below the permitted plant capacity" of 750,000 gallons.
The difference between those positions comes down partly to the plant's permit and its current design.
Permitted Capacity And Built Capacity
The Bear Creek plant's state permit allows up to 750,000 gallons a day. According to the city's permit application, the plant as built today is designed for 500,000 gallons a day.
The remaining capacity depends on an expansion that adds aeration basins and digesters. The application lists a construction start of April 2026 and a target of August 2027 for the expanded plant to begin operating. On Oct. 20, the council approved a $722,000 change order to add an aeration and digester basin as part of the plant's current expansion project.
By Lavon Weekly's math, the developer's projection of about 684,000 gallons a day equals about 91% of the plant's permitted capacity and is above the plant's current design capacity. Those projections describe full buildout, not today's flows. Both engineers' letters say actual flows will be evaluated as development occurs.
State rules set benchmarks for plant capacity. Under TCEQ's 75/90 rule, when a plant's flow reaches 75% of its permitted average flow for three consecutive months, the permit holder must begin engineering and financial planning for expansion. When flow reaches 90% for three consecutive months, the permit holder must obtain state authorization to begin construction of additional capacity.
The engineer's letter does not describe what the "recent flow restrictions" are or when they took effect, and the city has not addressed them publicly. The city's renewal application for the plant, received by the state in June, states that the plant is not under any enforcement action.
The City's Sewer System
According to the city's state filing, the Bear Creek plant serves all of Lavon except its eastern area, plus a utility district to the north, a collection system serving about 11,000 people. A second, smaller city plant on Elevon Parkway is permitted for 450,000 gallons a day.
The city has also applied for a permit for a new plant southeast of County Road 541 and FM 2755 that could treat up to 2.62 million gallons a day. In a notice issued Feb. 27, state staff announced a preliminary decision in favor of the permit. The application is still pending.
What Happens Tuesday
The council will consider Heritage Square's final plat, which lays out 16 lots and two common areas. City staff recommend approval, subject to final sign-off from the city engineer, fire marshal and planner. The council will also take a final vote on allowing the Lavon Economic Development Corporation to commit an estimated $2.7 million in future sales tax to the project over 15 years. The first vote, on Oct. 20, was unanimous.
The engineering review also includes a traffic study projecting about 22,890 vehicle trips a day at full buildout, with turn lanes planned on SH 78 and SH 205 and a traffic signal under study at SH 205 and Endeavour Boulevard.
Approving the plat does not issue building permits. Each lot will still require its own site and engineering plans before construction.
The council meets at 6:30 p.m. Tuesday at Lavon City Hall, 120 School Road.
What This Could Mean For Residents
The engineering documents focus on new development. They do not describe any change in service for homes and businesses already connected to the plant.
The documents also do not say how the city plans to respond to the restrictions, beyond the engineer's statement that the city is reviewing "other options." It is not yet known whether the restrictions could affect the timing of new development, the expansion schedule or sewer rates. Lavon's residential sewer rate has remained $53 a month for eight straight years.
Residents with questions can ask the city what the state restricted, how much of the plant's capacity is in use today, and when the expansion is expected to be complete. They can also speak for up to three minutes during citizen comments Tuesday. The engineering letters are in the city's Nov. 3 meeting packet.
