Contra Costa County, CA parcel and infrastructure data API

Parcel coverage in Contra Costa County

About 410,000 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:

Contra Costa County records do not include owner names. See pricing for credit costs.

Infrastructure in and around Contra Costa County

Example requests for Contra Costa 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 4180 TREAT BLVD, CONCORD, CA 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=4180 TREAT BLVD, CONCORD, CA' \
  https://api.korzy.co/api/search

import os
import requests

response = requests.get(
    "https://api.korzy.co/api/search",
    params={"q": "4180 TREAT BLVD, CONCORD, CA"},
    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": "06013-0ccfdec3454e77baad1a",
      "address": "4180 TREAT BLVD",
      "city": "CONCORD",
      "postcode": "94518",
      "county": "Contra Costa",
      "statefp": "06",
      "longitude": -122.00202961400032,
      "latitude": 37.954574,
      "match_type": "exact",
      "parcelid": "134062022",
      "parceladdr": "4180 TREAT BLVD",
      "parcelcity": "CONCORD",
      "situs_zip": "94518",
      "usedesc": "Office Buildings",
      "yearbuilt": 1978,
      "bldgsqft": 18100,
      "totalvalue": 3446150,
      "saledate": "1993-06-16",
      "updated": "2026-10-13",
      "geoid": "06013"
    }
  ],
  "truncated": false
}

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, 06013-0ccfdec3454e77baad1a, in records. 1 credit per 10 records requested.

curl --fail-with-body -sS --get \
  -H "Authorization: Bearer $KORZY_API_KEY" \
  --data-urlencode 'longitude=-122.00203' \
  --data-urlencode 'latitude=37.954574' \
  --data-urlencode 'limit=5' \
  https://api.korzy.co/api/query/point

const params = new URLSearchParams({"longitude": "-122.00203", "latitude": "37.954574", "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=-122.00203' \
  --data-urlencode 'latitude=37.954574' \
  https://api.korzy.co/api/utilities/context

import os
import requests

response = requests.get(
    "https://api.korzy.co/api/utilities/context",
    params={"longitude": "-122.00203", "latitude": "37.954574"},
    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": -122.00203,
  "latitude": 37.954574,
  "matches": {
    "water": [
      {
        "feature_id": "water:573",
        "name": "CONTRA COSTA WATER DISTRICT",
        "boundary_basis": "System Sourced"
      }
    ],
    "sewer": [
      {
        "feature_id": "sewer:4341",
        "name": "Central Contra Costa WWTF",
        "boundary_basis": "Modeled"
      }
    ]
  },
  "nearby_treatment": [
    {
      "feature_id": "treatment:9334",
      "name": "Central Contra Costa WWTF",
      "distance_km": 7.586875841648511
    },
    {
      "feature_id": "treatment:9333",
      "name": "MOUNTAIN VIEW WWTF",
      "distance_km": 11.041318098755095
    }
  ]
}

Contra Costa County data questions

How many parcels in Contra Costa County include year built?

About 350,000 of about 410,000 parcel records (85%) include year built.

Does the Korzy API return owner names for Contra Costa County parcels?

Contra Costa County parcel records do not include owner names. Values, land use and building facts are returned where the county publishes them.

How many data-center projects are in Contra Costa County?

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

How much power generation is in Contra Costa County?

About 40 operable power plants in Contra Costa County total about 4,200 MW of nameplate capacity, mainly natural gas, battery and pumped storage and wind.

Which water systems serve Contra Costa County?

Service areas of about 40 community water systems cover about 58% of Contra Costa County, and sewer service areas cover about 46%. /api/utilities/context returns the water and sewer matches at a point.

More featured counties

• Sacramento County, CABorders Contra Costa County · about 550,000 parcels
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• Riverside County, CAabout 990,000 parcels

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