Contact Us Ground Source, Inc. 216 E 5th St. Holton, KS 66436 785-364-2514 Thank you for your interest in Ground Source, Inc. and a geothermal comfort system. Please fill out the form below and someone will contact you shortly. We'll answer any questions you have and can provide you with a free estimate for your unique geothermal situation in Topeka and the surrounding region. Required Required Not a valid email Required Not a valid phone number Secret Answer Mailing Address is my Home Address Favorite National Publication