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MWELO in Commercial Development


Understanding Model Water Efficient Landscape Ordinance (MWELO)

As the demand for sustainable and environmentally responsible development grows, commercial developers are increasingly required to incorporate water-efficient MWELO practices into their projects.

According to a 2022 State Rankings Scorecard released by the Alliance for Water Efficiency, California, Texas, and Arizona were recognized as the leading states in water efficiency and conservation policies. California ranked highest, showcasing the most advanced measures in water efficiency, conservation, sustainability, and accessibility.2 This ranking highlights California’s leadership in setting stringent standards for water conservation, making it crucial for developers to understand and adhere to the MWELO practices to align with state regulations and promote sustainable development.

What is MWELO?

The Model Water Efficient Landscape Ordinance (MWELO) is a set of regulations designed to promote water conservation in landscapes, implemented at the state or local level. Established by the California Department of Water Resources, MWELO reduces outdoor water use by requiring efficient landscape design, mindful irrigation, and the selection of climate-appropriate plants. By setting clear guidelines, MWELO helps ensure that landscapes are designed and maintained in a way that maximizes water efficiency.

Key Components of MWELO

With water conservation strategies becoming increasingly stringent in regions like California, Texas, and Arizona, it is more important than ever for commercial developers to understand what is required. The following information outlines key components of MWELO that, when implemented effectively, reduce water consumption, and ensure compliance with evolving regulatory standards. This is essential for commercial developers aiming to enhance project resilience and maintain market competitiveness.

  1. Plant Selection:

MWELO encourages the use of climate-appropriate and drought-tolerant plants that require less water. This approach conserves water, supports local biodiversity, and reduces maintenance needs. 1

  1. Irrigation Efficiency:

Efficient irrigation plays a big part in implementing MWELO practices. The ordinance requires the use of weather-based or soil moisture-based irrigation controllers, as well as high-efficiency nozzles and drip irrigation systems. By implementing regular irrigation schedules water is applied only when and where it is needed.

  1. Soil Management:

Healthy soil is vital for water-efficient landscapes. MWELO mandates soil analysis and management practices that improve soil structure, water infiltration, and retention. This includes promoting soil water retention and reducing runoff using compost and other organic materials to enhance soil health. 1

  1. Mulch:

Utilizing mulch in your landscape reduces evaporation, improves soil health, and aids in slowing or eliminating the growth of unwanted weeds. As a protective layer over the soil, mulch maintains moisture during the hottest parts of the day, reducing the need for frequent watering.

  1. Hydrozoning:

By organizing plants in specific “zones” according to their watering needs, MWELO ensures that each zone receives only the amount of water needed which helps to prevent over- or under-watering.

  1. Water Budgets:

MWELO introduces the concept of a Maximum Applied Water Allowance (MAWA) and an Estimated Total Water Use (ETWU). These calculations set water budgets based on factors such as local climate, landscape area, plant types, and project size to limit overall water use. MAWA is based on these factors, while ETWU represents the actual water use anticipated for the landscape, including irrigation efficiency. 1

  1. Maintenance:

MWELO provides guidelines for ongoing landscape maintenance to ensure continued water efficiency. Proper maintenance practices, such as regular irrigation system checks, soil testing, and plant care, are essential for sustaining the benefits of water-efficient landscape design.


Benefits of MWELO for Commercial Developers

  1. Water Conservation:

By adhering to MWELO, commercial developers can significantly reduce outdoor water use. This helps conserve a vital natural resource and aligns with increasing regulatory requirements for sustainable development.

  1. Cost Savings:

Water-efficient landscapes often result in lower water bills and reduced maintenance costs. Efficient irrigation systems and drought-tolerant plants require less frequent watering and upkeep, leading to long-term financial savings for property owners and managers.

  1. Environmental Stewardship:

By minimizing water use, reducing runoff, and improving soil health, developers can create landscapes that support local ecosystems and biodiversity. This commitment to environmental stewardship can enhance a company’s reputation and appeal to eco-conscious tenants and clients.

  1. Regulatory Compliance:

Compliance with MWELO is mandatory for many projects in California. Understanding and adhering to its requirements ensures that developers avoid potential fines and project delays associated with non-compliance. It also positions developers to meet future regulatory changes as water conservation measures become more stringent.

  1. Market Competitiveness:

Incorporating MWELO-compliant landscapes provides a competitive edge in a crowded market. As awareness and demand for sustainability grow, properties that feature water-efficient landscapes will attract more tenants and buyers.

Local and state authorities may adopt MWELO or similar ordinances to address regional water conservation goals and respond to drought conditions. Developers, landscapers, and property owners must be aware of and comply with these regulations to contribute to sustainable water use practices.

Enhancing Landscape Sustainability

Stormwater Management & MWELO:

Effective stormwater management is an essential aspect of sustainable landscape design and can be easily integrated with MWELO guidelines. By incorporating features such as permeable pavements, rain gardens, and bioswales, developers can manage stormwater runoff efficiently. These practices not only help to prevent flooding and erosion but also enhance groundwater recharge and improve water quality.

For example, permeable pavements allow rainwater to infiltrate through the surface, reducing runoff and promoting groundwater recharge. Rain gardens and bioswales can capture and filter stormwater, removing pollutants before they reach water bodies. These stormwater management techniques complement MWELO’s goals by further enhancing water conservation and promoting a sustainable approach to landscape design.

Embracing MWELO for a Sustainable Future

Understanding and implementing the Model Water Efficient Landscape Ordinance (MWELO) is essential for commercial developers committed to sustainable and responsible development. By embracing MWELO’s guidelines, developers can achieve significant water savings, reduce costs, comply with regulations, and contribute positively to the environment. As water scarcity becomes an increasingly pressing issue, adopting water-efficient landscaping practices is not just a regulatory requirement but a strategic advantage in the development industry.

For more detailed information on specific water conservation strategies and to ensure your projects meet and exceed MWELO standards, we encourage you to get in touch with our Director of Landscape Architecture, Brandon Hanna, for additional resources and expert guidance.


Works Cited

  1. Alliance for Water Efficiency. “State Rankings Scorecard.” 2022.
  2. California Department of Water Resources. “Model Water Efficient Landscape Ordinance (MWELO).” n.d.