Summary of Montana's Water Reuse Guideline or Regulation for Landscaping

This page is part of the EPA’s REUSExplorer tool, which summarizes the different state level regulations or guidelines for water reuse for a variety of sources and end-uses.
The source water for this summary is Treated Municipal Wastewater.

On this page:

• Technical basis
• Water reuse for landscaping approved for use in Montana
• Water reuse treatment category for landscaping
• Additional context and definitions
• Water reuse for landscaping specifications (table)
• Upcoming state law or policy
• References
• Disclaimer

---

This page is a summary of the state’s water reuse law or policy and is provided for informational purposes only. Please always refer to the state for the most accurate and updated information. 

In Montana, water reuse for landscaping water reuse for landscapingThe use of recycled water on land to assist in the irrigation of vegetation in residential and non-residential areas. Includes impoundments to store water for irrigation , ornamental vegetation, parks, school yards, sporting facilities (including golf courses), private gardens, roadsides and greenbelts, and cemeteries. Excludes irrigation of areas used for agriculture, commercial reuse applications, or any centralized non-potable reuse. includes unrestricted and restricted access areas greater than, at or below the agronomic uptake rate. The source of water (treated municipal wastewater) treated municipal wastewater Treated wastewater effluent discharged from a centralized wastewater treatment plant of any size. Other terms referring to this source of water include domestic wastewater, treated wastewater effluent, reclaimed water, and treated sewage. is specified by the state as municipal wastewater. This write-up uses state terms when discussing sources or uses of water that may differ from the Regulations and End-Use Specifications Explorer's (REUSExplorer's) terms.

Technical basis

Montana approves the use of reclaimed water for reuse for landscape irrigation including the irrigation of areas with restricted and unrestricted access both greater than and at or below the agronomic uptake rate and impoundments (Circular DEQ 2). Montana requires that reclaimed wastewater reuse projects have documentation from the Department of Natural Resources and Conservation that the change of appropriation or water right was approved, or that no authorization is needed under Title 85, Water Use (Circular DEQ 2). All applicable provisions of the Clean Water Act (CWA) (33 U.S.C. §§ 1251 et seq.), including its implementing regulations, must be met. Montana does not require specific treatment for the reuse of reclaimed water for landscaping in areas where public access is expected. Treatment requirements and performance standards are applied for the removal of pathogen and chemical contaminants for water reuse for landscaping irrigation to ensure “an adequate demonstration of public health and environmental protection” (Circular DEQ 2). The technical basis for developing the specifications and/or removals of microbial contaminants, chemicals and other relevant indicators is not explicitly specified.

Water reuse for landscaping approved for use in Montana

Circular DEQ 2 defines the following approved water reuse for landscaping:

• Landscape impoundments (Class A-1)
• Irrigation of unrestricted access areas, such as golf courses, parks, playgrounds, school yards and residential landscapes
  • Greater than the agronomic uptake rate (Class A-1)
  • At or below the agronomic uptake rate (Class A)
• Irrigation of restricted access areas, such as cemeteries and freeway landscapes
  • Greater than the agronomic uptake rate (Class B-1)
  • At or below the agronomic uptake rate (Class C)

Water reuse treatment category for landscaping

The various classes of treatment are defined by their respective treatment requirements and applicable performance standards, differentiated by the degree of additional treatment provided following secondary treatment (Circular DEQ 2). The respective treatment requirements are briefly summarized for water reuse for landscaping.

• For Class A-1 reclaimed wastewater, the treatment requirements are secondary treatment, oxidation, coagulation, filtration and disinfection. Class A-1 reclaimed wastewater has an additional total nitrogen requirement that Class A and Class B-1 water do not. 
• For Class A reclaimed water, the treatment requirements are secondary treatment, oxidation, coagulation, filtration and disinfection.
• For Class B-1 reclaimed wastewater, the treatment requirements are secondary treatment, oxidation, settling and disinfection to achieve total coliforms ≤2.2 CFU/100 mL (7-day median) and ≤23 CFU/100 mL (single sample maximum). Class B-1 reclaimed wastewater has an additional total nitrogen requirement of ≤5 mg/L.
• For Class B reclaimed wastewater, the treatment requirements are secondary treatment, oxidation, settling and disinfection to achieve total coliforms ≤2.2 CFU/100 mL (7-day median) and ≤23 CFU/100 mL (single sample maximum).
• For Class C reclaimed wastewater, the treatment requirements are oxidation, settling and disinfection to achieve total coliforms ≤23 CFU/100 mL (7-day median) and ≤240 CFU/100 mL (single sample maximum).

Additional context and definitions

In Montana, reclaimed wastewater is defined as “wastewater treated by a public sewage system for reuse for private, public, or commercial purposes” (Circular DEQ 2). An impoundment is defined as “a basin, naturally formed or artificially built, which is dammed or excavated for the retention of water, slurry, sediment, waste or other liquid or semi-liquid material” (Mont. Code Ann. § 17-24-301). In Montana, “landscape use” includes decorative ponds of an ornamental nature (Circular DEQ 2). Restricted recreational impoundments include landscape ponds. Restricted recreational impoundments are defined as a body of reclaimed wastewater where recreation is limited to fishing, boating and other non-body-contact water recreation activities or a body of reclaimed wastewater used for aesthetic features or otherwise serves a function not intended to include public contact (Circular DEQ 2). 

Montana defines agronomic rate as controlled application of treated effluent (reclaimed wastewater) from public sewage treatment facilities to crops in a manner such that all nutrients are utilized by the crop and no impact to groundwater or surface water occurs.

Montana does not have public access buffer zones for Class A water but requires buffer zones of 50 feet for Class B and C reclaimed wastewater (Circular DEQ 2). No dwelling, residential property or areas with public access are allowed within the buffer zone. Montana requires that conveyance systems for the delivery of municipal reclaimed wastewater must be easily identifiable; the use of purple piping or purple striped piping is encouraged (Circular DEQ 2). Reclaimed water plumbing must not be cross connected to any potable water supply within the structure (Circular DEQ 1). Areas of reclaimed wastewater use must have signs posted at conspicuous public access points that read “Reclaimed wastewater – Do Not Drink” or an approved equivalent warning. 

Water reuse for landscaping specifications

Summary of Montana's Water Reuse for Landscaping Specifications

Source= Circular DEQ 2

* Information about sampling and monitoring requirements such as frequency, site and quantification methods not specifically listed in the table was not explicitly specified in the State-specific regulations.

^a Phosphorus monitoring might be required if there are changes in concentration of total inorganic phosphorus in ground water, if water quality protection practices approved by the department have been fully implemented and if an evaluation of the phosphorus adsorptive capacity of the soils in the area of the activity indicates that phosphorus will be removed for a period of 50 years prior to a discharge to any surface waters. Contact the state for more information on this. 

Upcoming state law or policy

No upcoming regulations pertaining to water reuse for landscaping were found for Montana.

References

Clean Water Act, 33 U.S.C. §§ 1251 et seq.

Design Standards for Public Sewage Systems, Circular DEQ 2.

Standard for Water Works, Circular DEQ 1.

Strip and Underground Mine Reclamation Act: Definitions and Strip Mine Permit Application Requirements, Definitions, Mont. Code Ann. § 17-24-301.
 

---

Disclaimers

Please contact us at [email protected] if the information on this page needs updating or if this state is updating or planning to update its laws and policies and we have not included that information on the news page.