Contact Us

Use the form on the right to contact us. 

We'll try to respond within 24 hours of receiving your message. If you don't hear from us, please check your junk email folder in case our response ends up there.



San Antonio, TX
United States

About Us

Flow-Know sprinkler controllers are designed and manufactured by Gray Line Systems, LLC in San Antonio, Texas.   

If you have a question about our controllers, or how to connect them to the Internet, send us a message and we'll be happy to help you get started.

If you're a landscape professional who would like to utilize Flow-Know controllers as part of your water management service, please email us to discuss how we might support you with additional training and technical support to help you achieve your business goals.

Voice/text: 210-452-1363, email:






Flow-Know: Save Water, Save Time, Save Money.

Flow-Know: Save Water, Save Time, Save Money.