Excavation and trenching - Wisconsin

Wisconsin is under federal OSHA jurisdiction which covers most private sector workers within the state. State and local government workers are not covered by federal OSHA.

Additional and different excavation rules are discussed below.

Open excavations in populous counties

In a town, city or village in a county with a population of 500,000 or more, no excavation for building purposes, whether or not completed, may be left open for more than 6 months without proceeding with the erection of a building on the excavation.

If an excavation remains open for more than 6 months, the building inspector or other designated officer of the town, village or city must order that the erection of a building on the excavation begin forthwith or that the excavation be filled to grade. If the owner of the land fails to comply with the order within 15 days after service of the order upon the owner, the building inspector or other designated officer will fill the excavation to grade, and the cost will be charged against the real estate.

Protection of adjoining property and buildings

Cave-in prevention. Any excavator must protect the excavation site to prevent the soil of adjoining property from caving in or settling.

Liability for underpinning and foundation extensions. If the excavation is made to a depth of 12 feet or less below grade, the excavator may not be held liable for the expense of any necessary underpinning or extension of the foundations of buildings on adjoining properties.

If the excavation is made to a depth more than 12 feet below grade, the excavator will be liable for the expense of any necessary underpinning or extension of the foundations of any adjoining buildings below the depth of 12 feet below grade.

The owners of adjoining buildings will be liable for the expense of any necessary underpinning or extension of the foundations of their buildings to a depth of 12 feet below grade.

Notice. Unless waived by adjoining owners, at least 30 days prior to commencing the excavation the excavator must notify, in writing, all owners of adjoining buildings of his or her intention to excavate. The notice must state that adjoining buildings may require permanent protection. The owners of adjoining property must have access to the excavation site for the purpose of protecting their buildings.

Damage to transmission facilities (utilities)

Excavators in Wisconsin must take all reasonable action to learn the location of any transmission facilities (i.e., pipes, pipelines, wires, cables, ducts, wirelines and associated facilities), including notifying a one-call state notification center of any proposed excavation, so that owners of the facilities can mark the facilities to avoid damage, interruption of service, or worker injury. The rules governing this process are found in Wis. Stat. § 182.0175.

Drainage for residential dwellings

The finished grade of the soil must slope away from a dwelling (one- or two-family residential construction) at a rate of at least 1/2 inch per foot for at least 10 feet. Where the finished surface is impenetrable, it must slope away from the dwelling for at least 10 feet at a rate that ensures equivalent drainage. Where lot lines, walls, slopes, or other barriers prevent having the 10-foot distance, swales or other means must be provided to ensure equivalent drainage away from the dwelling.

Erosion and sediment control for 1- or 2-family residential dwellings

General rules. Where land disturbing construction activity is to occur, erosion and sediment control practices must be employed and maintained to prevent or reduce the potential deposition of soil or sediment to the water of the state and adjacent properties.

Authority over erosion and sediment control at construction sites having a land-disturbance area of one acre or more was transferred to the Department of Natural Resources (DNR) under 2013 Wis. Act 20, sections 1712 and 2088. As a result, the Department of Safety and Professional Services no longer applies the following requirements to those sites.

Land disturbing construction activities, except those activities necessary to implement erosion or sediment control practices, may not begin until the sediment control practices are in place for each area to be disturbed in accordance with the approved plan.

Erosion and sediment control practices must be maintained until the disturbed areas are stabilized. A disturbed area will be considered stabilized by vegetation when a perennial cover has been established with a density of at least 70 percent.

Erosion and sediment control practices must either be approved by the department or listed by the DNR. Listed practices can be found through the Division of Industry Services website at http://dsps.wi.gov/programs/industry-services or by contacting the Division at telephone (608) 266-3151 or (877) 617-1565 or 411 (Telecommunications Relay).

Mandated practices. Specific practices at each site where land disturbing construction activity is to occur must be utilized to prevent or reduce:

• The deposition of soil from being tracked onto streets by vehicles.
• The discharge of sediment from disturbed areas into on-site storm water inlets.
• The discharge of sediment from disturbed areas into abutting waters of the state.
• The discharge of sediment from drainage ways that flow off the site.
• The discharge of sediment by dewatering activities.
• The discharge of sediment eroding from soil stockpiles existing for more than 7 days.

Control standards. In addition to the mandated practices, additional erosion and sediment control practices must be employed, as necessary, to accomplish one of the following:

• A potential annual cumulative soil loss rate of not more than one of the following:
  • Five tons per acre per year where sand, loamy sand, sandy loam, loam, sandy clay loam, clay loam, sandy clay, silty clay or clay textures are exposed.
  • Seven and 1/2 tons per acre per year where silt, silty clay loam, or silt loam textures are exposed.
• A reduction of at least 40 percent of the potential sediment load in storm water runoff from the site on an average annual basis as compared with no sediment or erosion controls for the site where less than one acre of land disturbing construction activity is to occur.

See Wis. Adm. Code SPS 325 Appendix A for further explanatory material regarding compliance solutions for 80 and 40 percent reductions.

Soil loss analysis. Potential soil loss must be determined using an engineer analytical modeling acceptable to the department. The Revised Universal Soil Loss Equation II is an example of an acceptable model to determine soil loss.

Monitoring. The owner must check the erosion and sediment control practices for maintenance needs at all the following intervals until the site is stabilized:

• At least weekly.
• Within 24 hours after a rainfall event of 0.5 inches or greater. A rainfall event will be considered to be the total amount of rainfall recorded in any continuous 24-hour period.
• At all intervals cited on the erosion and sediment control plan.

The owner must maintain a monitoring record when the land disturbing construction activity involves one or more acres. The monitoring record must contain:

• The condition of the erosion and sediment control practices at the intervals specified above.
• A description of the maintenance conducted to repair or replace erosion and sediment control practices.

Maintenance. The following maintenance rules apply:

• Off-site sediment deposition resulting from the failure of an erosion or sediment control practice must be cleaned up by the end of the next day. The Department of Natural Resources should be contacted before attempting to clean up any sediment deposited or discharged into the waters of the state.
• Off-site soil deposition, resulting from construction activity, which creates a nuisance must be cleaned up by the end of the workday.
• A municipality may enact more stringent requirements regarding cleanup of soil or sediment deposition onto public ways.
• The owner must complete repair or replacement of erosion and sediment control practices as necessary within 48 hours.
• When the failure of erosion or sediment control practices results in an immediate threat of sediment entering public sewers or the waters of the state, procedures must be implemented immediately to repair or replace the practices.

Excavations adjacent to an adjoining residential property

Notice. Any person making or causing an excavation which may affect the lateral soil support of adjoining one- or two- family residential dwellings must provide at least 30 days written notice to all owners of the intention to excavate. The notice must state that adjoining buildings may require permanent protection. The 30-day time limit for written notification may be waived if such waiver is signed by the owner(s) of the adjoining properties.

Underpinning and foundation extensions. If the excavation is made to a depth of 12 feet or less below grade, the person making or causing the excavation will not be responsible for any necessary underpinning or extension of the foundations of any adjoining buildings.

If the excavation is made to a depth in excess of 12 feet below grade, the owner(s) of adjoining buildings will be responsible for any necessary underpinning or extension of the foundations of their buildings to a depth of 12 feet below grade. The person making or causing the excavation will be responsible for any underpinning or extension of foundations below the depth of 12 feet below grade.

Excavation for footings and foundations

No excavation may be made below the footing and foundation unless provisions are taken to prevent the collapse of the footing or foundation. All footings must be located on undisturbed or compacted soil, free of organic material, unless the footings are reinforced to bridge poor soil conditions.

Adoption of the International Building Code

Wisconsin has adopted the International Building Code (2015) and incorporated it by reference into Wis. Adm. Code SPS 361 to 366 for all public buildings and places of employment, subject to the modifications found in Wis. Adm. Code SPS 361 and 362.