020-25 Wyo. Code R. § 25-19
(a) Commercial/industrial wastewater systems or combination commercial/industrial and domestic wastewater systems are subject to applicable requirements listed in sections 1 through 15 of this chapter, in addition to requirements in this section.
(b) If the wastewater is classified as, or determined to be hazardous, toxic, and/or contain petroleum products, the applicant shall demonstrate to the Administrator that any discharge or seepage from the wastewater facility will not cause a violation of the surface and/or groundwaters of the state in accordance with Chapter 1, "Quality Standards for Wyoming Surface Waters" and Chapter 8, "Quality Standards for Wyoming Groundwaters."
(c) If the impact of the hazardous, toxic, and/or petroleum products cannot be determined and mitigated, disposal of the wastewater using a soil absorption system shall be prohibited.
(d) Pre-treatment of the wastewater to remove the hazardous, toxic, and/or petroleum products shall be required prior to disposal if deemed necessary to protect the Groundwater(s) and Surface Water(s) of the State.
(e) The minimum horizontal setback distances (in feet) shown in Table 7 shall be maintained for commercial and industrial wastes and/or wastes greater than 2000 gallons per day but less than 10,000 gallons per day.
Table 7. Minimum Horizontal Setbacks for Commercial and Industrial Wastes in Feet1
| From | To Septic Tank Or Equivalent | To Absorption System |
| Wells (includes neighboring wells) | 50 | 200 |
| Public Water Supply Well | 100 | 5002 |
| Property Lines | 10 | 10 |
| Foundation Wall (w/o drains) | 5 | 10 |
| Foundation Wall (with drains) | 5 | 50 |
| Potable Water Pipes | 25 | 50 |
| Septic Tank | N/A | 10 |
| Surface Water, Spring (including seasonal and intermittent) | 50 | 100 |
| Cisterns | 50 | 50 |
1 For systems larger than 10,000 gallons per day, the isolation distance shall be determined by a hydrogeological study in accordance with Section 17(b) of Chapter 3, but shall not be less than those shown in Table 7.
2 Wastewater systems that discharge to the same aquifer that supplies a public water supply well and are located within Zone 1 or 2 (Attenuation) of the public water supply well, as determined by Wyoming Department of Environmental Quality Source Water Assessment Project (2004) or as established in Section 2 of the Wyoming Wellhead Protection Guidance Document (1997), shall provide additional treatment. These systems will be required to obtain an individual permit to construct and will require that a PE sign, stamp, and date the application, as stated in Section 2 of this chapter. The additional treatment shall be in accordance with Chapter 3, Section 2(b)(ii). The treatment shall reduce the nitrates to less than 10 mg/L of NO3- as N and provide 4-log removal of pathogens before the discharge leaves the property boundary of each small wastewater system.
020-25 Wyo. Code R. § 25-19
Adopted, Eff. 7/27/2016.
Amended, Eff. 6/29/2018.