Waukesha County, WI parcel and infrastructure data API

Parcel coverage in Waukesha County

About 160,000 parcel records with boundaries, situs addresses and parcel numbers, with the latest source update from October 2026. Each record has a stable korzy_id you can store and look up again with /api/parcel-record. Share of records with each field:

Owner name and mailing address are returned with include_owner=true, which doubles a request's cost: a parcel record costs 2 credits instead of 1. 96% of Waukesha County records carry an owner name.

Infrastructure in and around Waukesha County

Example requests for Waukesha County

Real responses from the production API, trimmed to the main fields. Every request needs an API key with api:read; see authentication and credits and limits.

1. Find a parcel by address

/api/search matches 1111 DELAFIELD ST, CITY OF WAUKESHA, WI and returns the parcel's korzy_id, coordinates and record. 1 credit.

curl --fail-with-body -sS --get \
  -H "Authorization: Bearer $KORZY_API_KEY" \
  --data-urlencode 'q=1111 DELAFIELD ST, CITY OF WAUKESHA, WI' \
  https://api.korzy.co/api/search

import os
import requests

response = requests.get(
    "https://api.korzy.co/api/search",
    params={"q": "1111 DELAFIELD ST, CITY OF WAUKESHA, WI"},
    headers={"Authorization": f"Bearer {os.environ['KORZY_API_KEY']}"},
    timeout=30,
)
response.raise_for_status()
parcel = response.json()["results"][0]
print(parcel["korzy_id"], parcel["longitude"], parcel["latitude"])

{
  "results": [
    {
      "korzy_id": "55133-4bb7e9c26adb01ed53b0",
      "address": "1111 DELAFIELD ST",
      "city": "CITY OF WAUKESHA",
      "postcode": "53186",
      "county": "Waukesha",
      "statefp": "55",
      "longitude": -88.23954336253178,
      "latitude": 43.023899650000004,
      "match_type": "exact",
      "parcelid": "WAKC0999990",
      "parceladdr": "1111 DELAFIELD ST",
      "parcelcity": "CITY OF WAUKESHA",
      "situs_zip": "53186",
      "land_use_code": "2",
      "taxacres": 0,
      "totalvalue": 23421400,
      "land_value_usd": 3232200,
      "improvement_value_usd": 24995800,
      "assessed_value_usd": 28228000,
      "market_value_usd": 28973500,
      "updated": "2025-01-01",
      "geoid": "55133"
    }
  ],
  "truncated": false
}

With include_owner=true (2 credits) the record adds owner fields, shown here as placeholders:

{
  "owner_name": "EXAMPLE HOLDINGS LLC",
  "owner_mailing_address": "100 EXAMPLE ST, SAMPLE CITY, ST 00000"
}

2. Look up the parcel at a point

/api/query/point returns every parcel whose boundary covers the coordinates; here it returns the same record, 55133-4bb7e9c26adb01ed53b0, in records. 1 credit per 10 records requested.

curl --fail-with-body -sS --get \
  -H "Authorization: Bearer $KORZY_API_KEY" \
  --data-urlencode 'longitude=-88.239543' \
  --data-urlencode 'latitude=43.0239' \
  --data-urlencode 'limit=5' \
  https://api.korzy.co/api/query/point

const params = new URLSearchParams({"longitude": "-88.239543", "latitude": "43.0239", "limit": "5"});
const response = await fetch(`https://api.korzy.co/api/query/point?${params}`, {
  headers: { Authorization: `Bearer ${process.env.KORZY_API_KEY}` },
});
if (!response.ok) throw new Error(`Korzy API ${response.status}`);
const { records } = await response.json();
console.log(records.map((record) => record.korzy_id));

3. Check water and sewer service

/api/utilities/context returns the water and sewer service areas at the point and the nearest treatment plants. 1 credit.

curl --fail-with-body -sS --get \
  -H "Authorization: Bearer $KORZY_API_KEY" \
  --data-urlencode 'longitude=-88.239543' \
  --data-urlencode 'latitude=43.0239' \
  https://api.korzy.co/api/utilities/context

import os
import requests

response = requests.get(
    "https://api.korzy.co/api/utilities/context",
    params={"longitude": "-88.239543", "latitude": "43.0239"},
    headers={"Authorization": f"Bearer {os.environ['KORZY_API_KEY']}"},
    timeout=30,
)
response.raise_for_status()
matches = response.json()["matches"]
print([area["name"] for area in matches["water"]])

{
  "longitude": -88.239543,
  "latitude": 43.0239,
  "matches": {
    "water": [
      {
        "feature_id": "water:41364",
        "name": "WAUKESHA WATER UTILITY",
        "boundary_basis": "System Sourced"
      }
    ],
    "sewer": [
      {
        "feature_id": "sewer:3260",
        "name": "WAUKESHA STP",
        "boundary_basis": "Sourced"
      }
    ]
  },
  "nearby_treatment": [
    {
      "feature_id": "treatment:11601",
      "name": "WAUKESHA STP",
      "distance_km": 3.0015898902716676
    },
    {
      "feature_id": "treatment:11343",
      "name": "BROOKFIELD - Fox River WPCC",
      "distance_km": 6.031472942406608
    }
  ]
}

Waukesha County data questions

How many parcels in Waukesha County include values?

About 150,000 of about 160,000 parcel records (94%) include values.

Does the Korzy API return owner names for Waukesha County parcels?

Yes. 96% of Waukesha County parcel records carry an owner name. Add include_owner=true to a point, search or parcel-record request; it doubles the request's cost, so a single parcel record costs 2 credits.

How many data-center projects are in Waukesha County?

Korzy tracks 2 data-center projects in Waukesha County: 1 operating and 1 status not reported. /api/datacenters/context lists projects within 10 km of any point.

How much power generation is in Waukesha County?

3 operable power plants in Waukesha County total about 15 MW of nameplate capacity, mainly other fuels and solar.

Which water systems serve Waukesha County?

Service areas of about 55 community water systems cover about 28% of Waukesha County, and sewer service areas cover about 53%. /api/utilities/context returns the water and sewer matches at a point.