Delaware Lead Service Line Inventory
Delaware's public lead-service-line transparency dashboard lets you check the material of the line connecting the main to your property. Here's how to use it.
Short answer: Check your utility's published lead service line inventory to see what material is listed for your address. Never assume a line is or isn't lead based on your home's age or neighborhood alone — only a verified inventory record or physical inspection tells you the material.
Delaware context
Public-system lead-service-line inventories, required under the federal Lead and Copper Rule, classify each line as lead, galvanized requiring replacement, non-lead, or unknown. Lead usually enters water through service lines or premise plumbing rather than the source water itself. An "unknown" classification does not mean lead — it means the material hasn't been verified yet.
Delaware lead-and-copper action levels
Delaware's Office of Drinking Water explains that the action level is 15 ppb for lead and 1.3 ppm for copper, based on the 90th percentile of monitored taps. Exceeding an action level triggers required system actions; it does not mean every tap has that concentration. Read the current DPH Lead and Copper Rule information and ask your utility how its inventory and sampling program apply to your address.
Step-by-step
- Find your water system (see Find Your Water System).
- Search for that utility's published lead service line inventory or lookup tool.
- Look up your address or account if an address-level lookup is available.
- If your line is listed as lead, galvanized requiring replacement, or unknown, review the utility's guidance on next steps.
- After any replacement or disturbance, follow the utility's flushing or filter guidance before drinking or cooking with tap water.
Common mistakes
- Assuming an older home automatically has a lead service line
- Treating "unknown" as equivalent to "confirmed lead"
- Confusing the service line (utility-to-property connection) with interior premise plumbing
- Skipping post-replacement flushing steps
When to contact the utility or a plumber
Contact your utility before any private plumbing work near the service line connection. A licensed plumber can address interior premise plumbing once you know whether the exterior line has been addressed. Full service-line replacement is generally preferable to partial replacement when replacement occurs.
Official sources
- Delaware DPH Lead and Copper Rule resources
- Delaware Code public-water reporting and notification provisions
- Your water utility's lead service line inventory
- U.S. EPA Lead and Copper Rule
Related
What does an "unknown" service line classification mean?
It means the utility hasn't yet verified the material of that specific line — not that it is confirmed lead. Follow the utility's guidance for next steps, which may include a home-side inspection.
This page provides general educational information and is not regulatory advice. Verify current requirements with your utility or ODW.
Last reviewed: 2026-07-11. Report a correction.