The Unspoken Price of Metal Manhole Covers (Replacement, Rust, and Theft)

Metal manhole covers, typically made of cast iron or ductile iron, have been a staple in urban infrastructure for decades. However, their hidden costs—driven by theft, rust, and frequent replacements—make them a financial burden for cities. Fiber Reinforced Plastic FRP manhole cover offer a cost-effective alternative, eliminating these expenses. Here’s a closer look at the hidden costs of metal covers and why FRP is the smarter choice.

Theft is a major issue with metal manhole covers. Their scrap value, often $50–$200 per cover, makes them a target for thieves, especially in developing nations or high-crime areas. Stolen covers create safety hazards, as open manholes endanger pedestrians and vehicles. Replacing a single cover costs $500–$2,000, including materials, labor, and traffic management. In some cities, hundreds of covers are stolen annually, leading to millions in unexpected expenses. FRP covers, with no scrap value, are rarely stolen, eliminating this cost entirely.

Rust is another hidden expense. Cast iron and ductile iron corrode in humid, coastal, or industrial environments, with wastewater systems accelerating degradation due to acidic gases. Rusted covers weaken, requiring regular maintenance like cleaning, painting, or galvanization. These treatments cost $100–$500 per cover every few years and don’t prevent eventual replacement. In corrosive environments, metal covers may last only 5–10 years, with replacements costing thousands per unit over a city’s infrastructure.

Maintenance adds to the burden. Beyond anti-corrosion treatments, metal covers often seize to frames due to rust or freezing, requiring labor-intensive removal. Inspections are frequent, as weakened covers can collapse under traffic, leading to accidents and liability costs. A single lawsuit from a collapsed cover can cost municipalities millions.

FRP manhole covers address these issues. Made from corrosion-resistant fiberglass and resin, FRP withstands moisture, chemicals, and UV exposure, with lifespans of 20–50 years. This eliminates rust-related maintenance and reduces replacements, saving cities 30–50% on long-term costs.

The non-stick qualities of FRP make inspections and repairs easier by preventing seizing.

The weight of metal covers—100–300 pounds—also drives costs. Installation and maintenance require heavy equipment and large crews, increasing labor expenses. Worker injuries from handling heavy covers raise insurance and downtime costs. FRP covers, weighing 20–50 pounds, can be handled by one or two workers, cutting labor costs by up to 50%.

Cities like Mumbai and London have faced spiraling costs from metal cover theft and corrosion, with some reporting annual losses of $1–2 million. Switching to FRP has slashed these expenses, with savings reinvested into roads and utilities. While metal covers may seem cheaper upfront, their hidden costs make them a poor long-term investment. FRP’s durability, theft resistance, and low maintenance make it the future of urban infrastructure.