7.11 Service Line Installation, Wet Tapping, Curb Stops & the Lead Service Line Inventory

From the main to the meter

WPI lists installing service lines including tapping, curb stops, and corporation stops as a distribution job task, alongside inspecting new construction. The service line is the shortest pipe in the system and generates a disproportionate share of the work orders, the leakage, and, since the Lead and Copper Rule Revisions, the regulatory attention.

Anatomy of a service connection

Working from the main outward:

1. Corporation stop (corp stop). The valve threaded or strapped directly into the main. It is the utility's shutoff at the main and is operated only when the service is installed or abandoned.
2. Service saddle or direct tap. A saddle clamps around the main and provides a threaded outlet, distributing the load and sealing against the pipe. Direct taps into ductile iron are possible for small sizes; saddles are required for PVC and for larger taps.
3. Service line (the "gooseneck" or setter connection). Historically a soft copper loop was left to accommodate settlement and main movement.
4. Curb stop and curb box. The shutoff at the property line, accessible from the surface with a curb key through the box. This is the utility's normal operating valve for a service.
5. Meter setter and meter, in a pit or inside the building.
6. Customer service line downstream of the meter, which is the customer's responsibility in most Colorado utilities.

Wet tapping

Most services are installed under pressure without interrupting service, using a tapping machine:

1. Clean and inspect the main at the tap location.
2. Install and tighten the service saddle evenly to the specified torque.
3. Thread the corporation stop into the saddle.
4. Mount the tapping machine on the corp stop, open the corp, and advance the drill through the pipe wall.
5. Retract the drill, close the corp, and remove the machine.
6. Connect the service tubing.

Details that matter: taps are placed at the 10 o'clock or 2 o'clock position, not at the top where air collects and not at the bottom where sediment does. Minimum spacing between taps and from joints and fittings is set by the standard specification. The coupon must be retrieved. And the entire assembly is disinfected before it is placed in service — the service is a direct connection to the potable main.

Materials

Lead service lines and the inventory requirement

The Lead and Copper Rule Revisions (LCRR) required every community and non-transient non-community water system to prepare and submit an initial service line inventory by October 16, 2024, classifying every service line — both the utility-owned and the customer-owned portion — as lead, galvanized requiring replacement, non-lead, or lead status unknown. Colorado systems submit through CDPHE, and the inventory must be made publicly accessible. Systems with lead, galvanized requiring replacement, or unknown lines must notify the affected customers.

Practical consequences for the distribution operator:

• Every dig is an inventory opportunity. When a service is exposed for any reason, the material of both the utility side and the customer side is identified and recorded. This is the primary way "unknown" classifications get resolved.
• Identification methods include visual inspection and the scratch-and-magnet test: lead is soft, scratches to a shiny silver-gray, and is not magnetic; galvanized steel is hard, scratches gray, and is magnetic; copper scratches to a copper color.
• Partial replacements are discouraged, because cutting a lead line can dislodge scale and temporarily increase lead release. Full replacement of both sides is the objective.
• After any service line disturbance — replacement, repair, or meter work on a known or possible lead line — the customer is instructed to flush thoroughly, and filters and follow-up sampling may be required.
• Lead release is driven by corrosion control, so distribution operators protect the phosphate or pH-alkalinity treatment that keeps the protective scale intact, and avoid changes in disinfectant, pH, or source that could destabilize it.

Service leaks

Services account for a large share of real losses because there are so many of them and because most service leaks never surface. A copper service pinhole under a paved street can run for years. Detection relies on acoustic listening at the curb stop and meter, correlation, and, where AMI exists, continuous-flow analysis at the meter.