Located in the Jiangnan water town region, Shaoxing features a dense network of rivers and an extended rainy season, posing significant challenges for municipal sewer cleaning operations—including high humidity and high operational frequency. In 2024, a municipal sanitation department in Shaoxing planned to procure a batch of blue license plate, 5-cubic-meter sewer cleaning trucks for routine maintenance of urban stormwater pipelines and tributary rivers. This was not the department’s first procurement—previously, it had purchased a similar batch of vehicles, but numerous issues emerged during actual use. This article traces the department’s real-world second procurement process, deconstructing vehicle selection logic, key technical requirements, and implementation details to provide practical reference for sanitation procurement professionals in southern China. I. The Pitfalls of the First Procurement: Why Did the Same Vehicle Rust Through in Just Two Years in Shaoxing? In 2021, the department procured five blue license plate sewer cleaning trucks for the first time at a unit price of approximately RMB 120,000 (based on publicly available tender information), using standard light-duty truck chassis. Within less than two years, multiple problems surfaced: • Severe corrosion of chassis and tank: With annual relative humidity consistently exceeding 70% and prolonged ground water accumulation during the rainy season, large-scale rust spots appeared on tank edges and chassis frame members coated with conventional paint; in some cases, weld seams even corroded through, causing leakage. • Premature aging and failure of sealing components: During operation, the vehicles require high-pressure flushing and sewage suction. Under hot-humid conditions, rubber seals—including those on the rear tank hatch, suction inlet, and hydraulic line connectors—hardened and cracked within one year, resulting in sewage leakage and strong odors at job sites. • System overheating due to high operational frequency: Rainfall in Shaoxing concentrates from June to September; after heavy rainstorms, sewer cleaning frequency surges dramatically. The original vehicles’ hydraulic pumps would overheat after continuous operation exceeding four hours, leading to sluggish actuation or automatic shutdown for thermal protection. • Slow maintenance response: As the chassis model was non-mainstream, spare parts had to be shipped from distant locations, resulting in repair lead times up to one week—seriously undermining emergency flood-control readiness. "Back then, we received more complaint calls each day than the total kilometers our cleaning trucks traveled," recalled the head of the department’s equipment division. "Especially during typhoon season, when vehicles broke down roadside, workers had no choice but to manually clear blockages—low efficiency and high risk." This experience taught the procurement team a critical lesson: selecting sewer cleaning trucks for southern China’s hot-humid climate cannot rely solely on purchase price or regulatory compliance—it demands rigorous evaluation of corrosion resistance, sealing performance, thermal management, and after-sales support as mandatory criteria. II. Avoiding Past Mistakes in the Second Procurement: Evolving Selection Logic—from 'Functional' to 'Durable' In 2024, the department launched a new procurement initiative for seven blue license plate, 5-cubic-meter sewer cleaning trucks, with a budget capped at approximately RMB 143,000 per unit (in line with local procurement norms). This time, the procurement team defined three core requirements: 1. Corrosion-Resistant Coating: Must pass a 200-hour salt-spray test without red rust formation. The procurement team explicitly stipulated in the tender documents that both tank and chassis must be coated with epoxy zinc-rich primer plus polyurethane topcoat, with a minimum dry-film thickness of 120 μm—and required submission of third-party salt-spray test report