The buried water and sewer facilities to residential properties are privately owned after the water valve and at the property line for the sewer. They can sometimes be challenging to locate for ground disturbance projects.
When digging on private property, we strongly suggest that you always have these two facilities located, however, sometimes they cannot be located for a variety of reasons (i.e., no building access, cannot find the valve, plastic water line, no visible cleanout etc.). When a locate limitation for water and sewer is present, a private locate technician should classify the work area as a critical work zone for excavation-type work.
The following three scenarios will give you an idea of how a private locate technician should identify the utility-critical zone for water and sewer at a residential home to help reduce your risk:
1. WATER
Draw a straight line from each building corner to the water valve:

The Critical Zone when a water line cannot be located, you know that the water exits the front of the building, and where the water valve is located at the property line.
2. SEWER (Sewer Building Exit Identified)
Draw a straight line from each property line corner to the sewer where it exits the building:

The Critical Zone when a sewer line cannot be located and you know the sewer exits the front of the building.
3. SEWER AND WATER (Building Exit Unknown)
Draw a straight line from each property line corner to the sewer where it exits the building:

The Critical Zone when water and sewer lines cannot be located, you do not know where they exit at the front of the building. This scenario assumes they exit the front of the building, however, if they exit on either side of the building (which does happen), the Critical Zone includes the sides of the building as well.
If a private locate critical zone is identified, we suggest any excavation activities be hand dug or vacuum excavated within the critical zone and within 2 meters from all outside edges of the identified critical zone.
There are many other types of critical zones on private property and if you want to hear more on this topic, please drop us a line at locates@premierlocates.ca. We welcome all comments or suggestions for any of our posts.