Service Description: This is a layer of water service boundaries for 45,973 community water systems that deliver tap water to 307.7 million people in the US. This amounts to 97% of the population reportedly served by active community water systems and 93% of active community water systems. The layer is based on multiple data sources and a methodology developed by SimpleLab and collaborators called a Tiered, Explicit, Match, and Model approach–or TEMM, for short. The name of the approach reflects exactly how the nationwide data layer was developed. The TEMM is composed of three hierarchical tiers, arranged by data and model fidelity. First, we use explicit water service boundaries provided by states. These are spatial polygon data, typically provided at the state-level. We call systems with explicit boundaries Tier 1. In the absence of explicit water service boundary data, we use a matching algorithm to match water systems to the boundary of a town or city. When multiple water systems match to the same TIGER boundary, we employ a "best match" algorithm that assigns one water system to one TIGER place based on features like population served and other locational information about the water system. Finally, in the absence of an explicit water service boundary (Tier 1) or a TIGER place polygon match (Tier 2), a statistical model trained on explicit water service boundary data (Tier 1) is used to estimate a reasonable radius at provided water system centroids, and model a spherical water system boundary (Tier 3). Water system centroids are taken from the ECHO database; however, where a system centroid is labeled as a county or state centroid, we take several steps to assign a better centroid.
Population coverage rates per Tier, for systems with population reported:
- Tier 1: 49.3% population covered
- Tier 2: 35.13% population covered
- Tier 3: 12.9% population covered
Active community water systems coverage rates per Tier:
- Tier 1: 35.7%
- Tier 2: 22.42%
- Tier 3: 34.9%
Service ItemId: 12fac2ae328143549d93048f3565457e
Has Versioned Data: false
Max Record Count: 2000
Supported query Formats: JSON
Supports applyEdits with GlobalIds: False
Supports Shared Templates: True
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Spatial Reference: 4326 (4326)
Initial Extent:
XMin: -120.051978802107
YMin: 33.5924989363248
XMax: -117.937022918955
YMax: 35.4881018099237
Spatial Reference: 4326 (4326)
Full Extent:
XMin: -119.5823
YMin: 33.2122600000001
XMax: -117.62749706
YMax: 35.3611415060001
Spatial Reference: 4326 (4326)
Units: esriDecimalDegrees
Child Resources:
Info
SharedTemplates
Supported Operations:
Query
ConvertFormat
Get Estimates