Willow Grove Mill
EPA ID: DE0020122 · 3,090 people served · 3 ZIP codes
Federal monitoring spanning five full years has produced zero violations at Willow Grove Mill — a clean record across every reporting cycle for a utility serving approximately 3,090 residents.
Data: EPA SDWIS Last verified: 2026-04-02
Service Area Map
Coverage area for Willow Grove Mill Source: EPA SDWIS service area boundaries.
Service area boundary
Service Area Demographics
The Willow Grove Mill serves a community with a median household income of $129,971 and an estimated 65,199 residents across its service area. Approximately 40% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
💧 Where Does Your Water Come From?
Willow Grove Mill's water is pumped from underground aquifers. Groundwater is naturally filtered through rock and soil, but it can be vulnerable to PFAS contamination, nitrates from agriculture, and industrial chemicals that seep into the water table.
About 1% of homes in New Castle County, Delaware rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Superfund Proximity Note: This service area ranks in the 90th percentile nationally for proximity to Superfund (NPL) sites. Groundwater sources near contaminated sites may face elevated risk from industrial chemicals.
Infrastructure Risk
Comparable Water Systems
Similar-sized systems in Delaware
Estimated Remediation Costs
Average estimated costs across ZIP codes served by this system
Based on national averages for common remediation projects. Actual costs vary by property. Only issues flagged by EPA, FEMA, or state data for each ZIP code are included.
System Overview
Willow Grove Mill (EPA ID: DE0020122) is a community water system in Delaware that serves approximately 3,090 people from groundwater sources.
This system provides water to 3 ZIP codes across 3 communities.
Violation History
Lead & Copper
No Lead and Copper Rule sampling data available for this water system.
Need help with your water quality?
Typical cost: Water test: typically $20–$50 (DIY kit) · Professional inspection: $150–$400
Find the Right Water FilterFree tip: Let cold water run for 2 minutes before drinking — this helps flush lead from your pipes.
ZIP Codes Served
Coverage: Service area ZIP codes sourced from EPA Community Water System Service Area Boundaries v3 (March 2026 release). These ZIPs reflect the actual deployment footprint recorded by DE or modeled from parcel and building-footprint data.
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Willow Grove Mill (DE0020122) on EPA.gov.
Frequently Asked Questions
Is Willow Grove Mill water safe to drink?
Based on EPA records, Willow Grove Mill has no recorded violations in the past 5 years — a positive indicator of water quality management.
How many people does Willow Grove Mill serve?
Willow Grove Mill serves approximately 3,090 people across 3 ZIP codes in Delaware.
Where does Willow Grove Mill get its water?
The primary water source is groundwater.
Lead Service Line Inventory
Service line breakdown reported under the federal Lead and Copper Rule Improvements (LCRI) inventory requirement:
This system reports zero confirmed lead service lines in its inventory. Unknown-material counts may still warrant verification.
Federal LCRI rule (effective October 2024) requires every public water system to inventory its service lines and complete lead-line replacement within 10 years.
Source: EPA SDWIS Federal Service Line Inventory (Phase 2) · Submitted 2026
ZipCheckup is not affiliated with the utility or state agency. Inventory figures render verbatim from the public LCRI submission cited above; ZipCheckup does not perform inspections or replacements.
How Water Systems Appear in Rankings
Water systems are evaluated by violation history, contaminant detections, and service population. Larger systems with more service connections appear in more rankings.