[Published: 13 October 2026 | Last updated: 13 October 2026] | 5 min read
TL;DR
- Most cast iron storm drain covers weigh between 80 and 300 lb (Neenah Foundry, accessed 2026), and a standard 24-inch municipal cover is usually 100 to 150 lb.
- Roadway catch basin grates are heavier. New York City requires a minimum of 425 lb for its Type R grating (NYC DEP, 2025).
- A frame adds 75 to 250 lb on top of the cover (Neenah Foundry, accessed 2026).
- Diameter drives weight more than any other factor, followed by material and load rating.
- Small residential grates are far lighter. A 9-inch square ductile iron grate weighs 7.89 lb (NDS, 2023).
How Heavy Is a Storm Drain Cover?
A typical cast iron storm drain cover weighs 80 to 300 lb, and a standard 24-inch municipal cover comes in around 100 to 150 lb (Neenah Foundry, accessed 2026). Light-duty covers can weigh under 70 lb, while large traffic-rated covers can top 400 lb.
The City of Albuquerque gives a precise example. Its standard 24-inch storm manhole cover weighs 180 lb, and the 36-inch version weighs 355 lb (City of Albuquerque, 2011). Both figures cover the lid only, not the frame.
What Is a Storm Drain Cover?
A storm drain cover is the lid or grate that sits over an opening in a stormwater system. This article uses “storm drain cover” for both types.
A solid lid is a manhole cover, which gives workers access to the pipe below. A slotted grate, used at a catch basin (a box that collects surface runoff), lets rainwater flow in. Both sit in a cast frame set into the road or pavement.
Storm Drain Cover Weight by Type and Size
Weight depends on the cover’s job. The table below lists published figures from manufacturers and public agencies.
| Cover type | Typical weight | Source |
|---|---|---|
| 9-inch square residential grate (ductile iron) | 7.89 lb | NDS, 2023 |
| Light-duty cast iron cover | Under 70 lb | Neenah Foundry, accessed 2026 |
| Standard 24-inch municipal cover | 100 to 150 lb | Neenah Foundry, accessed 2026 |
| 24-inch storm manhole cover (Albuquerque standard) | 180 lb | City of Albuquerque, 2011 |
| 36-inch storm manhole cover (Albuquerque standard) | 355 lb | City of Albuquerque, 2011 |
| Large traffic-rated cover | Over 400 lb | Neenah Foundry, accessed 2026 |
| NYC Type R catch basin grating (minimum) | 425 lb | NYC DEP, 2025 |
What Determines the Weight of a Storm Drain Cover?
Diameter is the biggest driver of weight (Neenah Foundry, accessed 2026). Going from a 24-inch to a 36-inch Albuquerque cover roughly doubles the weight, from 180 lb to 355 lb.
Three other factors matter:
- Material: cast iron and ductile iron are the heaviest common options, while composite and plastic covers weigh much less.
- Load rating: a cover built for highway traffic needs more iron than one over a patio or walkway.
- Design features: ribbing, gussets, and hinges all add mass.
The frame is a separate weight. A cast iron frame adds 75 to 250 lb, so a complete 24-inch H-20 assembly often reaches 300 lb or more (Neenah Foundry, accessed 2026). Albuquerque’s 24-inch standard shows this: a 180 lb cover plus a 145 lb frame totals 325 lb (City of Albuquerque, 2011).
Why Are Storm Drain Covers So Heavy?
Storm drain covers are heavy because they carry vehicle traffic over an open pipe. A cover rated H-20 must support up to 16,000 lb on a single axle (Neenah Foundry, accessed 2026).
Think of the cover as a small bridge deck over a hole. The wider the opening and the heavier the wheel load, the more iron it takes to span the gap without cracking. The same logic applies to catch basin grates, which New York City designs for HS20-44 highway loading (NYC DEP, 2025).
How to Find the Weight of a Specific Storm Drain Cover
The most reliable way is to check the manufacturer’s specification or the local agency’s standard drawing. Many city drawings list cover and frame weights separately, as Albuquerque’s does.
NYC DEP requires manufacturer identification, a cast date or heat number, and country of origin cast into each piece (NYC DEP, 2025). Those markings let you look up the exact product. If no markings are readable, weighing the cover directly is the only certain method.
Do not lift a cover by hand without the right tools. At 100 lb or more, a cover can cause back injuries and crushed fingers. Crews use lifting hooks or a wheeled cover dolly instead.
Common Mistakes When Estimating Storm Drain Cover Weight
- Quoting the lid weight as the whole assembly. The frame can double the total, so confirm which one a number refers to.
- Assuming all covers are the same size. A grate for a residential catch basin and a roadway grate differ by hundreds of pounds.
- Using a generic range for a purchase or lifting plan. Ranges like 80 to 300 lb are estimates, so get the product’s published weight before ordering freight or hiring equipment.
Frequently Asked Questions About Storm Drain Cover Weight
How much does a storm drain cover weigh on average?
There is no single average. Most cast iron covers fall between 80 and 300 lb, and a 24-inch municipal cover is usually 100 to 150 lb (Neenah Foundry, accessed 2026).
How much does a 24-inch storm drain cover weigh?
A 24-inch cover typically weighs 100 to 150 lb. Albuquerque’s standard storm cover in that size is 180 lb, with a 145 lb frame (City of Albuquerque, 2011).
How heavy is a catch basin grate?
Roadway catch basin grates are heavier than most round covers. New York City sets a minimum weight of 425 lb for its Type R grating (NYC DEP, 2025). Small residential grates are much lighter, such as the 7.89 lb NDS 9-inch grate (NDS, 2023).
How much does the frame add to the total weight?
A cast iron frame adds 75 to 250 lb, depending on size and design (Neenah Foundry, accessed 2026).
Why are storm drain covers made of cast iron?
Cast iron has high compressive strength and a relatively low cost, which is why it has been the standard material for manhole covers. Ductile iron is a stronger variant with similar weight.
Are there lighter storm drain covers?
Yes. Composite materials such as fiberglass-reinforced polymers and recycled plastics weigh far less than iron, though they suit lighter load ratings. Plastic grates are common for patios and walkways.
Can one person lift a storm drain cover?
A small residential grate, yes. A municipal cover of 100 lb or more should be lifted with a hook or dolly, and a 180 lb or larger cover needs equipment or a crew.
Key Takeaways
- Most storm drain covers weigh 80 to 300 lb, with large and roadway-rated ones going well past 400 lb.
- Size, material, and load rating decide the weight, and diameter has the biggest effect.
- Always add the frame when planning transport or installation.
- Check the manufacturer’s spec or the agency’s standard drawing for the exact weight.
References
- Neenah Foundry, “How Much Does a Manhole Cover Weigh, and Why Does It Matter?” – https://neenahfoundry.com/blog/how-much-does-a-manhole-cover-weigh-and-why-does-it-matter/
- City of Albuquerque, Standard Drawing 2110, Storm Manhole Frame and Covers (January 2011) – https://dmdmaps.cabq.gov/HydroTrans/H09D017/work%20order/COA%20STD%20DWG%202110.pdf
- NYC Department of Environmental Protection, Sewer Design Standards (revised September 2025) – https://www.nyc.gov/assets/ddc/downloads/publications/NYCDEPSEWERDESIGNSTANDARDS_RevisedSep2025.pdf
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