US Bridges

ST 18 Main ST over Water Mill River

Fair

Norfolk County, Massachusetts · .16 KM N of ST 3 · Structure no. W32028349DOTNBI

Built
1957
68 years old
Condition
Fair
inspected January 2025
Type
Culvert
Concrete
Length
36 ft
2 main spans
Daily traffic
47,300
2025 count
Owner
State
State Highway Agency

About this bridge

ST 18 Main ST over Water Mill River is a concrete culvert carrying ST 18 Main ST over Water Mill River in Norfolk County, Massachusetts. It was built in 1957, so it is 68 years old, older than the Massachusetts average of 63.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 47,300 vehicles a day, roughly 4% of them trucks, projected to reach 56,381 by 2032. The structure is 36 ft (11 m) long and 188 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesST 18 Main ST
CrossesWater Mill River
Location.16 KM N of ST 3
RouteState Highway 18
CountyNorfolk County
StateMassachusetts
Coordinates42.19601, -70.95574
Functional classUrban Other Principal Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Channel and channel protection7 GoodSome minor problems.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating110.1 US tons
Inventory rating110.1 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans2
Design loadH 20
Structure length36 ft (11 m)
Longest span17 ft (5.2 m)
Deck width188 ft (57.3 m)
Roadway width78 ft (23.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic47,300 (2025)
Projected traffic56,381 by 2032
Trucks4%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedOther structural work, including hydraulic replacements
Estimated improvement cost$521,000 (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was ST 18 Main ST over Water Mill River built?

It was built in 1957, making it 68 years old in 2025.

What condition is ST 18 Main ST over Water Mill River in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in January 2025.

How much traffic does ST 18 Main ST over Water Mill River carry?

About 47,300 vehicles per day (2025 count), of which roughly 4% are trucks.

How long is ST 18 Main ST over Water Mill River?

The structure is 36 ft (11 m) long with a longest span of 17 ft (5.2 m) and a deck 188 ft wide.

Who owns ST 18 Main ST over Water Mill River?

It is owned by the State Highway Agency.