# sdwis.water.service_areas

Look up the geographic service areas of EPA-regulated public water systems. Returns counties, cities, and zip codes served by each utility, along with area type and tribal codes. Filter by state or county to discover which water systems serve a specific area. Filter by PWSID to get all geographic areas served by a specific utility. Useful for mapping water service boundaries, identifying utilities for an address, or understanding the geographic scope of a water quality issue. Data source: EPA SDWIS Federal Reporting Services Geographic Areas table, US Gov public domain.

Agent View of the PolicyLayer registry record for `sdwis.water.service_areas`. HTML page: https://policylayer.com/tools/io-github-whiteknightonhorse-apibase/sdwis.water.service-areas

## Facts

- Tool: `sdwis.water.service_areas`
- Server: Apibase (`apibase-mcp-client`) — https://policylayer.com/tools/io-github-whiteknightonhorse-apibase.md
- Install: `npx -y apibase-mcp-client`
- Homepage: https://github.com/whiteknightonhorse/APIbase
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server auth posture: open
- Server rate-limited: no
- Parameters: 4
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `limit` | integer | no | Maximum number of service area records to return (1–100, default 20) |
| `pwsid` | string | no | Public Water System Identifier (PWSID) to get service areas for a specific system (e.g. CA3310067) |
| `state` | string | no | State or primacy agency code to filter service areas (e.g. CA, TX, FL) |
| `county` | string | no | County name served by the water system (e.g. LOS ANGELES) |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "sdwis.water.service_areas",
    "arguments": {}
  }
}
```

## Why sdwis.water.service_areas is rated Low

Retrieves EPA public water system service area data without side effects or data modification.

From the tool's own definition: "Look up geographic service areas, returns counties, cities, zip codes. No modification or deletion."

## Use case

AI agents call sdwis.water.service_areas to retrieve information from Apibase without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Apibase:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "sdwis.water.service_areas": {}
  }
}
```

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## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=io-github-whiteknightonhorse-apibase · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-whiteknightonhorse-apibase