> ## Documentation Index
> Fetch the complete documentation index at: https://docs.powerhq.co/llms.txt
> Use this file to discover all available pages before exploring further.

# utilities: Look Up Electric Utilities Serving a ZIP

> Retrieve the utility or TDU serving a given ZIP code. Use the returned utility ID to fetch residential plans for that specific provider.

The `utilities` query returns the electric utility or Transmission and Distribution Utility (TDU) serving a given ZIP code. Run this query first whenever you need to resolve a valid `utilityId` before fetching residential plans — it ensures you're querying plans for the exact provider that serves your customer's address.

## Parameters

<ParamField query="zipCode" type="String" required>
  The five-digit ZIP code to look up. Returns all utilities serving that ZIP code.
</ParamField>

## Example

```graphql theme={null}
{
  utilities(zipCode: "75231") {
    id
    name
  }
}
```

```json theme={null}
{
  "data": {
    "utilities": [
      { "id": "ONCOR", "name": "Oncor" }
    ]
  }
}
```

## Nesting residential plans

You can request residential plans directly inside the `utilities` response by adding a `residentialPlans` selection to your query. This lets you retrieve the utility and its available plans in a single round trip.

```graphql theme={null}
{
  utilities(zipCode: "75231") {
    id
    name
    residentialPlans {
      title
      price
      term
    }
  }
}
```

## Response fields

<ResponseField name="id" type="ID">
  The utility or TDU identifier (for example, `"ONCOR"`). Pass this value as the `utilityId` argument to `residentialPlans` for precise plan lookup scoped to a specific TDU.
</ResponseField>

<ResponseField name="name" type="String">
  The human-readable name of the utility (for example, `"Oncor"`).
</ResponseField>

<ResponseField name="residentialPlans" type="[ResidentialPlan!]">
  Optional. Residential electricity plans offered under this utility. Include this field in your selection set to retrieve plans in the same query rather than making a separate `residentialPlans` call.
</ResponseField>

<Tip>
  Use the `id` returned here as the `utilityId` argument when calling [`residentialPlans`](/queries/residential-plans). Scoping plan queries to a specific TDU produces more accurate results and avoids cross-utility plan matches.
</Tip>