diff --git a/README.md b/README.md
index 25a5152..e0aec7d 100644
--- a/README.md
+++ b/README.md
@@ -703,6 +703,7 @@ API | Description | Auth | HTTPS | CORS |
 | [PM25.in](http://www.pm25.in/api_doc)| Air quality of China | `apiKey` | No| Unknown |
 | [PVWatts](https://developer.nrel.gov/docs/solar/pvwatts/v6/) | Energy production photovoltaic (PV) energy systems | `apiKey` | Yes | Unknown |
 | [Srp Energy](https://srpenergy-api-client-python.readthedocs.io/en/latest/api.html)| Hourly usage energy report for Srp customers | `apiKey` | Yes | No|
+| [Thames Water Open Data](https://data.thameswater.co.uk) | Open Data from the UK's largest water and wastewater services company | `apiKey` | Yes | Unknown |
 | [UK Carbon Intensity](https://carbon-intensity.github.io/api-definitions/#carbon-intensity-api-v1-0-0) | The Official Carbon Intensity API for Great Britain developed by National Grid | No | Yes | Unknown |
 | [Website Carbon](https://api.websitecarbon.com/) | API to estimate the carbon footprint of loading web pages| No | Yes | Unknown |