Summary of Delaware'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 Delaware
- 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 Delaware, water reuse for 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 spray irrigation onto unlimited and limited public access sites. The source of water 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 domestic and 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
Delaware approves the use of domestic and municipal wastewater for reuse for landscape irrigation in areas with limited and unlimited public access (7-60 Del. Admin. Code). All applicable provisions of the Clean Water Act (CWA) (33 U.S.C. §§ 1251 et seq.), including its implementing regulations, must be met. Reclaimed water used for landscape irrigation is separated into two categories with different treatment requirements and performance standards based on site-access control (i.e., spray irrigation with unlimited and limited public access). Treatment requirements and performance standards are applied for the removal of microbial contaminants, chemicals and other relevant indicators for water reuse for landscaping are summarized in the table. 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 Delaware
7-60 Del. Admin. Code defines the following approved water reuse for landscaping:
- Spray irrigation onto unlimited public access sites (e.g., landscaped areas, golf courses, parks and roadway medians)
- Spray irrigation onto limited public access sites
Water reuse treatment category for landscaping
In Delaware, all wastewater used for irrigation on unlimited access sites must be biologically treated, filtered and disinfected. State guidelines indicate that, “this level of treatment is required to protect the health of persons who may come in contact with the irrigated wastewater” (7-60 Del. Admin. Code).
Wastewater effluent standards for domestic and municipal wastewater for BOD5, total suspended solids and disinfection are based on site access control. In cases where public access cannot be restricted, levels of wastewater treatment need to be increased to assure comparable public health safeguards exist.
Requirements include a comprehensive analysis to determine surface water impacts including the fate and transport of nitrogen and phosphorus and impact of with respect to dissolved oxygen, Enterococcus bacteria, total nitrogen and total phosphorus. This comprehensive analysis is part of the Surface Water Assessment Report that is submitted to demonstrate that nutrient performance standards for wastewater are being met at the post treatment location prior to reach the closest receiving surface water body.
Additional context and definitions
Spray irrigation is defined as the controlled application of treated wastewater to a vegetated soil surface. Application can occur in areas where public access cannot be restricted, such as landscaped areas, golf courses, parks and roadway medians.
Water reuse for landscaping specifications
Summary of Delaware's Water Reuse for Landscaping Specifications
| Recycled Water Class/Category | Source Water Type | Water Quality Parameter | Specification | Sampling/Monitoring Requirements (Frequency of monitoring; site/ location of sample; quantification methods)* |
|---|---|---|---|---|
|
Spray irrigation, unlimited public access sites (Included but not limited to landscaped areas, golf courses, parks and roadway medians) |
Municipal and domestic wastewater |
Fecal coliform |
≤20 colonies/100 mL |
Daily permissible average concentrations (turbidity should be continuously monitored online) |
|
5-day biochemical oxygen demand (BOD5) |
≤10 mg/L |
|||
|
Turbidity |
≤5 NTU |
|||
|
Total suspended solids (TSS) |
≤10 mg/L |
|||
|
Chlorine residual (if chlorine used for disinfection) |
0.5–4 mg/L chlorine residual |
Must be maintained at compliance monitoring point prior to irrigation |
||
|
UV disinfection (if UV used for disinfection) |
≥100 mJ/cm2 |
UV disinfection must be performed following storage and routine sampling for its effectiveness must be performed at the compliance monitoring point |
||
|
Nitrogen |
Provided the site suitability evaluation reports do not delineate more stringent requirements, the nitrogen and phosphorus requirements outlined in Exhibit MM in 7 Del. Admin Code § 7101-6.0 apply |
Not specified |
||
|
Phosphorus |
Not specified |
|||
|
Spray irrigation, limited public access sites |
Municipal and domestic wastewater |
Fecal coliform |
≤200 colonies/100 mL |
Daily permissible average concentrations |
|
5-day biochemical oxygen demand biochemical oxygen demand (BOD5) |
≤50 mg/L |
|||
|
Total suspended solids (TSS) |
≤50 mg/L (mechanical systems) ≤90 mg/L (ponds) |
|||
|
Nitrogen |
Provided the site suitability evaluation reports do not delineate more stringent requirements, the nitrogen and phosphorus requirements outlined in Exhibit MM in 7 Del. Admin Code § 7101-6.0 apply |
Not specified |
||
|
Phosphorus |
Not specified |
Source= 7-60 Del. Admin. Code
* 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.
Upcoming state law or policy
No upcoming regulations pertaining to water reuse for landscaping were found for Delaware.
References
Clean Water Act, 33 U.S.C. §§ 1251 et seq.
Large On-site Wastewater Treatment and Disposal System (LOWRDS) Performance Standards, 7 Del. Admin. Code § 7101-6.0.
Regulations Governing the Design, Installation and Operation of On-Site Wastewater Treatment and Disposal Systems, 7-60 Del. Admin. Code.
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.