Summary of Minnesota’s Water Reuse Guideline or Regulation for Onsite Non-potable Water Reuse
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 Rainwater Collected Onsite.
On this page:
- Technical basis
- Types of onsite non-potable reuse approved for use in Minnesota
- Water reuse category/type
- Additional context and definitions
- Onsite non-potable reuse 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 Minnesota, onsite non-potable water reuse The use of treated onsite collected waters for non-potable purposes at the single-building or district scale. This reuse application excludes the use of recycled water from a centralized treatment and distribution system for landscape irrigation or commercial uses. applications include water closets, urinals, tap primers for floor drains and floor sinks, industrial processes, landscaping, water features, vehicle washing facilities, cooling tower makeup and other similar uses. The source of water rainwater collected onsite Precipitation collected at the district or regional scale is classified separately under 'stormwater.' is specified by the state as harvested rainwater. The 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
Minnesota approves the use of both above and below ground rainwater catchment systems for onsite non-potable water reuse applications, including water closets, urinals, tap primers for floor drains and floor sinks, industrial processes, landscaping, water features, vehicle washing facilities, cooling tower makeup and other similar uses (Minn. Stat. § 4714.1602.1). In Minnesota, all harvested rainwater is limited to collection from roof surfaces made of hard, impervious material (Minn. Stat. § 4714.1602.7.4). All applicable provisions of the Clean Water Act (CWA) (33 U.S.C. §§ 1251 et seq.), including its implementing regulations, must be met in addition to any state water quality standards. In Minnesota, a permit is required for the construction, installation and alteration of a rainwater catchment systems (Minn. Stat. § 4714.1601). A permit is issued for a rainwater catchment system following submittal and approval of complete plumbing plans by the commissioner (Minn. Stat. § 1300.0215.6). Treatment requirements and performance standards are applied for the removal of debris, microbial contaminants, chemicals and other relevant indicators related to onsite non-potable water reuse and are summarized in the table. The technical basis for developing the specifications and/or removal of debris, microbial contaminants, chemicals and other relevant indicators is not explicitly specified.
Types of onsite non-potable reuse approved for use in Minnesota
Minnesota defines the following specific onsite non-potable water reuse applications for treated rainwater from rainwater catchment systems (Minn. Stat. § 4714.1602.1):
- Water closets,
- Urinals,
- Tap primers for floor drains and floor sinks,
- Industrial processes,
- Landscaping,
- Water features,
- Vehicle washing facilities,
- Cooling tower makeup,
- Similar uses approved by the commissioner.
Additional onsite non-potable water reuse applications for treated rainwater from rainwater collection and distribution systems are not specified.
Water reuse category/type
Minnesota does not assign harvested rainwater used for onsite non-potable water reuse to a category or class but “the rainwater catchment system shall include filtration and disinfection to maintain the minimum water quality requirements” as reported in the table (Minn. Stat. § 4714.1603.12). Additional water quality requirements may apply dependent on the intended application (Minn. Stat. § 4714.1601.7).
Specific treatment requirements are provided for non-potable rainwater catchment systems; however, these requirements are not specific to the use of harvested rainwater for onsite non-potable water reuse applications. Devices and equipment used to treat harvested rainwater must be designed, sized and documented by a Minnesota-registered professional engineer (Minn. Stat. § 4714.1603.12). Briefly, these treatment requirements include:
- Filtration and disinfection: All non-potable rainwater catchment systems must include a debris excluder or other approved means to prevent debris from entering the storage tank (MPC, 2020). Filtration in the form of a 100-micron absolute filter is required along with disinfection to provide a 3.5-log reduction of bacteria (Minn. Stat. § 4714.1603.12). Minnesota requires harvested rainwater to be treated as necessary to meet water quality requirements specific for the intended onsite water reuse application, included those provided in the table (Minn. Stat. § 4714.1602).
Additional context and definitions
Minnesota outlines specific requirements on the collection, distribution and drainage materials of rainwater catchment systems. In Minnesota, collection of rainwater is limited to above-ground impervious roofing surfaces (Minn. Stat. § 4714.1602.7.4; Minn. Stat. § 4714.1602.9.3). Water supply and distribution materials utilized in rainwater catchment systems must comply with Table 604.1 and be constructed of like materials (MPC, 2020). Rainwater catchment and drainage materials utilized in rainwater catchment systems including gutters, downspouts and leaders must comply with storm drainage requirements outlined by MPC (2020).
Minnesota requires all maintenance, testing and inspection of non-potable rainwater catchment systems to be recorded in the form of a maintenance log by the property owner and available for inspection (MPC, 2020). Following the construction of a rainwater catchment system, an operation and maintenance manual is required. The manual must include detailed diagram of the system, instructions for operating and maintaining the system, details on maintaining required water quality, details on deactivating the system, applicable testing, inspection and maintenance frequencies and manufacturer contact information (MPC, 2020).
Minnesota requires specific design elements when implementing rainwater collection practices. Rainwater catchment systems must be compatible with the pipe and fitting materials, water treatment and water conditions (MPC, 2020). Rainwater storage tanks must be constructed of solid, durable, water-tight materials not subject to excessive corrosion or decay (Minn. Stat. § 4714.1603.2). All components of the storage tanks must be designed with room for cleanout and inspection (MPC, 2020). Minnesota allows both above and below grade non-potable water storage tanks, under the requirements summarized in the 2020 Minnesota Plumbing Code (MPC).
All non-potable water storage tanks must be made identifiable with signage with the words “NONPOTABLE RAINWATER” (MPC, 2020). Commercial and institutional restrooms using nonpotable rainwater for water closets or urinals require signage made visible to users with the words “TO CONSERVE WATER, THIS BUILDING USES RAINWATER TO *____*” where *____* indicates rainwater usage (Minn. Stat. § 4714.1604.2). Equipment rooms containing non-potable rainwater equipment must have a sign posted with the words “CAUTION NONPOTABLE RAINWATER DO NOT DRINK. DO NOT CONNECT TO DRINKING WATER SYSTEM. NOTICE: CONTACT BUILDING MANAGEMENT BEFORE PERFORMING ANY WORK ON THIS WATER SYSTEM” (MPC, 2020).
Onsite non-potable reuse specifications
Summary of Minnesota's Onsite Non-potable Reuse Specifications
| Recycled Water Class/Category (Approved Uses) | Source Water Type | Water Quality Parameter | Specification | Sampling/Monitoring Requirements (Frequency of monitoring; site/ location of sample; quantification methods)*,a |
|---|---|---|---|---|
| Onsite non-potable water reuse | Rainwater | E. coli | 2.2 MPN/100 mL |
100-micron absolute filter with disinfection to provide a ≥3.5-log reduction of bacteria. After installation and monthly thereafter. Exception: Every 12 months thereafter when electronically monitored. |
| Odor | Non-offensive |
After installation and monthly thereafter. Exception: Every 12 months thereafter when electronically monitored. |
||
| Temperature | Measured and recordedb |
After installation and monthly thereafter. Exception: Every 12 months thereafter when electronically monitored. |
||
| Color | Measured and recorded |
After installation and monthly thereafter. Exception: Every 12 months thereafter when electronically monitored. |
||
| pH | Measured and recorded |
After installation and monthly thereafter. Exception: Every 12 months thereafter when electronically monitored. |
||
| Debris (e.g., leaves, needles, sediment) | Filters and screens free of debris | Inspect, clean or replace (where necessary) every three months. | ||
| Roof, gutters, downspouts and roof washers free of debris | Inspect and clean at beginning of seasonal usage and monthly during seasonal usage. | |||
| Overhanging tree branches and vegetation | Remove as needed. | |||
| Storage tanks and locking devices free of debris | Clear, inspect and verify operation after initial installation and every 12 months thereafter. |
Source = Minn. Stat. § 4714.1602.9.6; Minn. Stat. § 4714.1601.5; MPC (2020)
* 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 Rainwater catchment systems and components must be inspected and maintained in accordance with this column unless more frequent inspection is required by the manufacturer.
b A maintenance log for rainwater catchment system is required in accordance with Minn. Stat. § 4714.1601.3 and must be maintained by property owner, including record of testing, inspection and maintenance.
Upcoming state law or policy:
No upcoming onsite non-potable water reuse regulations related to rainwater were found for Minnesota.
References:
Clean Water Act, 33 U.S.C. §§ 1251 et seq.
General, Minn. Stat. § 4714.1601 (2022).
Inspection and Testing, Minn. Stat. § 4714.1605 (2021).
Minnesota Department of Health. 2018. Advancing Safe and Sustainable Water Reuse in Minnesota: 2018 Report of the Interagency Workgroup on Water Reuse.
Minnesota Plumbing Code (MPC). 2020. Chapter 16: Nonpotable Rainwater Catchment Systems.
Nonpotable Rainwater Catchment Systems, Minn. Stat. § 4714.1602 (2022).
Plumbing, Minn. Stat. § 4714.1605 (2016).
Rainwater Storage Tanks, Minn. Stat. § 4714.1603 (2021).
Signs, Minn. Stat. § 4714.1604 (2021).
Please contact us at waterreuse@epa.gov 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.