Every driver has felt it: that jarring thump as wheels pass over a manhole sitting unevenly in the road surface. What feels like a minor annoyance is actually a symptom of a widespread infrastructure problem with serious financial, safety, and environmental consequences. The American Society of Civil Engineers reported in its 2021 report card that 43% of public roadways in the United States are in poor or mediocre condition. With manholes located approximately every 300 feet in cities and suburbs, the sheer number of potential problem points is staggering. Poor manhole installation acts much like a Hidden Beam in a structure — invisible until it fails, but carrying enormous hidden loads. When a manhole does not sit at the correct elevation, it triggers a cascade of failures that cost contractors, municipalities, and taxpayers far more than most realize.
John Hickey, executive director of the Asphalt Pavement Association of Oregon, sums it up plainly: “Go out on any road and the chances are high that you will see a manhole that does not match the surrounding pavement. When a manhole is not at the right elevation, it is difficult to compact the surrounding asphalt correctly. That asphalt is going to fail way earlier than all the other asphalt on the road.” Understanding the full scope of these costs is the first step toward fixing them.
The Pavement Integrity Problem
According to the National Asphalt Paving Association, 93% of America’s paved roads are surfaced with asphalt. When laid correctly, asphalt pavement should last 15 to 20 years. Manhole installations that sit above or below grade dramatically shorten that lifespan. The problem is mechanical: when a manhole rim sits too high, the paver rides up over it, leaving less asphalt around the edges. When it sits too low, water pools in the depression, seeps into the base layers, and accelerates cracking through freeze-thaw cycles.
How Misaligned Manholes Damage Pavement
The failure mechanism follows a predictable pattern:
- The manhole rim is set above or below the designed pavement grade during installation.
- Asphalt placed around the rim cannot be compacted to the same density as the surrounding mat.
- Lower-density asphalt cracks under traffic loads, typically within 1 to 3 years instead of 15.
- Water infiltrates through cracks, softening the base course and accelerating pavement failure.
- The entire section around the manhole must be cut out, the utility cover releveled, and the area repaved.
Compounding Factors in Complex Paving Conditions
Straight sections of road with no intersections and no curbs are the easiest paving scenarios. Real-world conditions are rarely that simple. Modern road construction involves multiple variables that make precise manhole leveling both more difficult and more critical:
- Multiple underground utilities clustered at intersections.
- Automatic grade control systems on pavers that struggle to transition around fixed metal obstructions.
- ADA-compliant curb ramps and cross-slope requirements.
- Complex drainage gradients that change elevation across the road width.
- Milled surfaces being overlaid with new asphalt at varying thicknesses.
- Intersections where paving direction changes and joints form near utility covers.
Each of these variables increases the difficulty of achieving proper manhole elevation, and each one compounds the risk of premature pavement failure. The more precisely a manhole cover matches the designed pavement elevation, the longer the surrounding pavement will last.
Worker Safety Risks and the Skills Gap
The construction industry is facing a well-documented labor shortage, and the experience level of available workers is declining. According to data from the U.S. Bureau of Labor Statistics cited in Construction Executive, 34.9% of new untrained workers in construction are injured during their first year on the job. This statistic is especially relevant to manhole installation, where traditional methods create predictable safety hazards.
The Problem with Manual Shim Methods
For decades, the standard method for raising manholes to grade has involved pry bars, shims, bricks, concrete chunks, and whatever else happens to be in the contractor’s bucket. Crew members manually lift heavy cast iron rings while coworkers slide shims underneath. This process creates several safety risks:
- Back injuries from lifting and prying heavy manhole components into position.
- Hand and finger injuries from working in tight clearances between the manhole ring and the pavement.
- Crush injuries if a ring slips during the lifting process.
- Repetitive strain from the constant bending, lifting, and adjusting required across multiple manholes on a single job.
Why Experience Matters Less with Modern Systems
Hickey notes that experienced crew members who can pave well are becoming increasingly rare. Left with inexperienced crews, there is an elevated risk of both quality issues and injuries. Bolt-adjusted leveling systems eliminate the need for manual lifting and shimming entirely. A single worker can adjust manhole elevation using threaded bolts, removing the safety hazards associated with pry bars and heavy lifting. This is one area where investing in better tools directly reduces both injury risk and installation error, much like Using Metal Detectors in Woodworking a Practical Guide demonstrates how the right tool prevents damage from hidden obstructions.
Equipment, Vehicle, and Liability Costs
The costs of poorly leveled manholes extend far beyond the pavement itself. Contractors, municipalities, and private citizens all bear financial consequences that are rarely accounted for in project budgets.
Damage to Paving and Maintenance Equipment
Asphalt pavers, milling machines, and sweepers are expensive pieces of equipment that operate in close contact with the road surface. When an auger or mill head strikes the raised edge of an uneven manhole, the results can be costly:
| Equipment Component | Potential Damage | Typical Repair Cost Range |
|---|---|---|
| Asphalt auger | Bent or broken flighting from impact with raised rim | $2,000 to $8,000 |
| Auger gearbox | Geartooth shearing or housing cracking from shock load | $5,000 to $15,000 |
| Milling drum teeth | Breakage or accelerated wear from striking metal | $500 to $3,000 per incident |
| Screed plate | Gouging or warping from riding over raised cover | $1,500 to $6,000 |
| Sweeper broom | Bristle damage and frame stress | $800 to $4,000 |
Beyond the direct repair costs, the downtime created by equipment failure delays road repair schedules and forces crews to mobilize again at additional expense. These hidden costs are similar to the financial surprises that arise when Who Pays for Unexpected Soil Problems During Construction goes unaddressed in the planning phase.
Vehicle Damage and Public Liability
For the driving public, off-kilter manhole covers represent a real hazard. Vehicles that hit an uneven manhole at speed can suffer:
- Tire sidewall bulges or punctures from catching a sharp metal edge.
- Bent or cracked wheel rims, particularly on low-profile tires.
- Damaged suspension components, including struts, control arms, and ball joints.
- Alignment problems that accelerate tire wear.
Motorcyclists face the gravest risk. A motorcycle tire catching the edge of an elevated manhole can cause an immediate loss of control, leading to serious injury or death. Municipalities that have been notified of dangerous manholes and failed to act face significant liability exposure. The cost of a single lawsuit can dwarf the expense of proper manhole installation many times over.
The Cost of Delays and Rerouting
When a manhole-related pavement failure forces emergency road repairs, the indirect costs multiply rapidly:
- Traffic detours must be planned and signed, often requiring traffic control crews and equipment.
- Emergency repair crews cost premium rates compared to planned work.
- Businesses along affected routes lose foot traffic and customer access.
- Commuters lose productive time sitting in unexpected delays.
- Emergency vehicle response times increase when detours are in place.
These costs are rarely tracked or attributed to the original manhole installation, but they represent real economic losses that accumulate every time a bad installation fails and has to be redone.
Environmental Impact and Long-Term Infrastructure Planning
As climate change drives more intense weather events, the environmental consequences of poorly installed manholes become increasingly serious. Extreme weather affects road integrity in multiple ways, and manholes at incorrect elevations compound the damage.
Water Infiltration and Stormwater Management
A manhole rim that sits below the pavement grade creates a depression that collects stormwater. When that water seeps around the manhole frame and into the underground system, it causes:
- Increased inflow and infiltration (I&I) into sanitary sewer systems, overwhelming treatment plants.
- Soil erosion around the manhole structure, leading to settlement and further misalignment.
- Accelerated pavement deterioration through freeze-thaw damage in cold climates.
- Greater risk of sewage overflows during heavy rain events, as excess water enters the system.
In 2017, 47% of manholes were flooded during intense rainfall events in surveyed urban areas, sometimes leading to sewage spills and infrastructure damage. Proper manhole elevation and sealing is a critical part of climate resilience planning that is often overlooked.
Material Waste and Resource Efficiency
Every time a manhole-related pavement failure is repaired, old asphalt must be removed and new material brought in. This consumes aggregate resources, generates truck traffic, and produces emissions from cutting, hauling, and paving equipment. When manholes are installed correctly the first time with bolt-adjusted leveling systems, these frequent repair cycles are avoided, saving both material and energy over the pavement’s design life.
The Age of Existing Infrastructure
Most manholes in service today are nearly 100 years old, and many newer ones are still raised to grade using shims made of bricks, concrete chunks, or other construction debris. This improvisational approach, while common, is no longer acceptable by modern standards. Available technologies such as screw-adjusted and bolt-adjusted manhole leveling systems allow crews to achieve precise grade tolerances every time, regardless of skill level. These systems represent a small upfront investment that pays for itself many times over through reduced repairs, fewer injuries, and longer pavement life.
The parallels with other construction details are instructive. Just as Hidfast Hidden Decking Fasteners Installation Comparison Guide shows how choosing the right fastening system prevents future deck failures, choosing the right manhole leveling system prevents future pavement failures. Both decisions involve a slightly higher upfront cost in exchange for dramatically better long-term performance.
A Path Forward
The many costs of bad manholes are borne by road builders, contractors, municipalities, insurance companies, drivers, and taxpayers. There is no reason for these costs to persist when simple, proven solutions exist to ensure manholes are set right the first time. Engineers can design safety into their specifications by requiring bolt-adjusted or screw-adjusted leveling systems. Contractors can protect their crews by replacing manual shim methods with adjustable hardware. And municipalities can reduce long-term maintenance costs by adopting modern manhole installation standards.
When manholes are properly leveled, drivers do not notice them at all. That invisibility is the mark of good installation. Achieving it consistently requires moving beyond age-old methods and adopting the precision tools that the modern construction industry deserves.