Posted on Thursday September 20, 2012


All Iowans are required by law to notify the Iowa One Call System at least 48 hours (excluding Saturdays, Sundays and legal holidays) prior to engaging in any type of digging or excavating. Homeowners and private residents are not exempt from making this important notice.

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What constitutes digging and excavating (When notification to Iowa One Call is required)?

Anytime you plan to excavate, including digging. Whether it’s a small or a large construction project or homeowner project, call Iowa One Call at least 48 hours prior to excavating (excluding weekends and/or holidays). Iowa One Call will notify the owners/operators of underground facilities who participate in Iowa One Call. The various underground facility operators will dispatch “locate” personnel to the area to mark the underground facility locations with flags and paint markings, showing where underground facilities are located so the excavator can avoid damaging the facilities.

Iowa law applies to professional contractors as well as homeowners, and encompasses a wide array of outdoor projects including:

  • Installing a fence
  • Planting trees or shrubs
  • Building a patio, addition, deck, garage, outdoor shed or any similar structure that requires any form of digging
  • Putting in a new driveway
  • Installing a septic system or water drainage system
  • Terracing or landscaping

How to initiate a locate request through the Iowa One Call System

Information required for requesting locate facilities:

When you call, please be prepared to give an Iowa One Call operator the following information:

Within a city:

  • A street address or block and lot numbers, or both, of the proposed area of excavation.
  • The name and address of the excavator.
  • The excavator’s telephone number.
  • The type and extent of the proposed excavation.
  • Whether the discharge of explosives is anticipated.
  • The date and time when excavation is scheduled to begin.
  • Approximate location of the excavation on the property.
  • If known, the name of the housing development and property owner.

Outside a city:

  • The name of the county, township, range, and section.
  • The name and address of the excavator.
  • The excavator’s telephone number.
  • The type and extent of the proposed excavation.
  • Whether the discharge of explosives is anticipated.
  • The date and time when excavation is scheduled to begin.
  • Approximate location of the excavation on the property.
  • If known, the quarter section, E911 address and global positioning system coordinate, name of the property owner, name of housing development with street address or block and lot numbers, or both.

Each locate request processed is assigned an eight-digit serial number by the computer. This number contains all the information about your call. It is important to write this number down and keep it with your records. Iowa One Call retains this information for six years.

* If you need additional assistance, call your local County Recorder’s office.

Location Accuracy is Important

A common mistake in utility locates is not properly identifying your excavation/digging location. Prior to making a request, be sure to determine whether your excavation site is located in a village/city or a township. Often, your mailing address may include the name of the nearest village/city, when you are actually located in a township.

How to identify the actual site where planed excavations may occur (“White-Lining”)

The best way to identify the proposed excavation area for the locators who apply the markings is to white line the area prior to their arrival. Marking the proposed excavation area in white allows the locators to concentrate their efforts in a specific area, which allows for more accurate markings and safer locates. White lining is a process that enhances communication between the excavators and locators and should be practiced at all excavation sites. Another advantage of white lining is the reduction of paint and flags at the site, which can become an eyesore to property owners.

What do the colored flags and paint marking placed at proposed excavation sites mean?

Underground Utility Markings
What the Markings Mean

American Public Works Association Utility Location & Coordination Council Uniform Color Code:

RED Electric Power Lines, Cables, Conduit and Lighting Cables
YELLOW Gas, Oil, Steam, Petroleum or Gaseous Materials
ORANGE Communication, Alarm or Signal Lines, Cables or Conduit
BLUE Water, Irrigation and Slurry Lines
GREEN Sewers and Drain Lines
PINK Temporary Survey Markings
WHITE Proposed Excavation
PURPLE Reclaimed Water

Am I liable for damaging underground facilities?

All excavators, including homeowners, may be liable for any damages they cause to underground facilities. Simply calling Iowa One Call does not relieve an excavator of these liabilities. Excavators need to take precautions and dig safely to avoid damaging buried facilities. In the event an underground facility is damaged, the responsible excavator (including homeowners) may be liable for the repair costs, loss of product/services, property damage, etc. In the event the locate markings are clearly inaccurate the liability for damages may shift to the facility operator.

How accurate are the markings?

Underground facilities will be marked with paint and/or colored flags to approximate the location of the buried facilities. Iowa law allows for an 18-inch Tolerance Zone on each side of the buried facility. Excavators should try to avoid digging in this tolerance zone. If your plans demand that you must excavate in the tolerance zone, Iowa law requires that the buried facility within that tolerance zone be exposed. You expose the buried facility by hand digging with extreme caution. You must not use any type of power equipment to expose a buried facility within the tolerance zone (vacuum excavation is an example of an accepted means of exposing a buried facility in the tolerance zone other than hand digging).

Keep in mind that the 18 inches is to be measured from both sides of the buried facility. While most buried facilities in a homeowner’s yard are no greater than 2 inches in diameter, some facilities may be larger (18 inches on either side of a 4 inch facility requires a 40 inch tolerance zone – refer to chart). If you must excavate within the tolerance zone it is a good idea to call the operator of the buried facility (i.e.: gas & electric utility company, telephone company, etc.) to verify the size/diameter of the facility in question.

How long are the locate markings good for?

Under Iowa law the locate markings are good for as long as they are maintained and clearly visible. It is the responsibility of the excavator to maintain the original markings throughout the duration of the excavation even if it requires establishing reference points in the event the markings may be destroyed. Iowa law requires that the facility operators apply the markings in a manner that will last a minimum of five days on non-permanent surfaces and ten days on permanent surfaces. At the end of the five or ten-day period, depending on the surface type, excavators may call for relocates if they are not able to maintain the markings. However, to be compliant with the law, excavators must take the necessary precautions to maintain the original markings. Keep in mind that the original markings applied by the facility owners/operators (through their in-house or subcontracted locators) must not be altered. In the event a relocate is needed, the excavator should use the existing dig-ticket number as a reference for the call center operators. Iowa One Call does error on the side of caution. However, contractors and excavators must not take the system for granted. Misuse of the system will be reported to the Iowa One Call Board of Directors and possibly the Iowa Attorney General.

Are all underground facilities located and marked (“Private Facilities”)