Is onsite water reuse right for my project?

You have likely heard the familiar sustainability adage: reduce, reuse, recycle. But have you heard it applied to water? If you’ve read our background on wastewater reuse blog, you know that our focus at Epic is to transition the industry toward a more circular approach for water and wastewater management. Our goal is to implement onsite wastewater reuse in as many projects as possible —by reducing potable demand, reusing water, and recycling wastewater resources, onsite reuse can accomplish all three of the R’s. A true sustainability slam dunk.

However, we also know that not all projects are suited for onsite reuse. There are many factors to weigh aside from sustainability impact: cost-benefit, regulations, market fit, and more. If you are considering onsite reuse for your project and whether it check’s all of the boxes, this high-level outline will help inform that decision-making process. And as always, we’re happy to answer any questions you have as it relates to your specific project.

Key Takeaways

Onsite water reuse is not a one-size-fits-all solution. Feasibility depends on the project’s size, location, water demand, regulations, budget, and sustainability goals.
Larger buildings and multifamily properties are often stronger candidates because higher water use can create more opportunities to reduce municipal water and sewer costs.
The most feasible projects have consistent non-potable water demands, such as toilet and urinal flushing, laundry, irrigation, cooling equipment makeup, ornamental water features, or clothes washing.
Local regulations, incentives, grants, and utility rates can significantly influence whether onsite water reuse is required, financially attractive, or easier to justify.
New construction projects may offer more flexibility because recycled water piping, tanks, and treatment equipment can be planned early, while retrofits require a closer look at available space and plumbing infrastructure.

Considerations for onsite water reuse in buildings

While each project is unique, below are a few considerations that are most helpful in determining if a project is a good fit for onsite water reuse technology.

Location & gross square feet (GSF)

Utility rates remain one of the biggest factors in onsite water reuse feasibility. In a 2025 survey of major U.S. cities, combined annual residential water and sewer charges at 120 HCF, or about 90,000 gallons, were $3,280 in Seattle, $2,333.04 in Atlanta, and $1,569.54 in New York City. The same survey reported an average of $1,789.18 across the listed major cities.

For commercial properties, a separate 2025 comparison of annual water and sewer user charges found that Seattle had standardized annual commercial charges of $44,209, Atlanta had $28,922, and New York City had $16,863. These figures help illustrate why location can have such a large impact on ROI, but they do not translate directly into a universal payback period. Actual payback depends on the building’s water balance, system size, reuse applications, installation cost, annual O&M, incentives, and local permitting requirements.

In Seattle, combined annual residential water and sewer charges were $3,280 in 2025 at 120 HCF, or approximately 90,000 gallons, making it one of the higher-cost markets in the survey. Multifamily projects in Seattle may have stronger cost-offset potential, but payback should be calculated using project-specific water use, system cost, O&M, and reuse demand.
In Seattle, standardized annual commercial water and sewer user charges were $44,209 in a 2025 comparison of 30 large U.S. cities. For a large office building, that means water and sewer savings may be meaningful, but an updated blackwater system payback estimate requires current project-level assumptions.
In Atlanta, combined annual residential water and sewer charges were $2,333.04 in 2025 at 120 HCF, or approximately 90,000 gallons. This was above the major-city average in the survey, which supports the case for evaluating onsite reuse in large multifamily projects with consistent non-potable demand.
In New York City, the combined water and sewer rate as of July 1, 2026 is $13.86 per 100 cubic feet, or 748 gallons. A 2025 commercial comparison listed New York City’s standardized annual commercial water and sewer user charges at $16,863. For added context, WateReuse Association cites an existing New York City onsite water reuse system with approximately $360,000 in annual net operating savings, a $1.9 million initial capital investment, and a payback period of roughly 3.5 years; however, that is a separate project and should not be presented as the payback period for every 500,000-square-foot office building.

These simplified examples give an idea of how size and location affect the financial return of a wastewater treatment system. The calculations also assume that water is being reused for flushing, laundry (as applicable), and cooling towers, and include estimates for design/system cost as well as annual O&M. They do not include installation costs, which will vary by region. The end use demands of your project may be different, which will change the analysis considerably.

In general, the more water usage that the onsite treatment system can replace, the better.

Available end use

Once water is recycled and treated, where will it be utilized? Identifying available end uses for recycled water is an essential decision in the design process.

Luckily, there are many options! United States regulations allow wastewater to be reused for toilet and urinal flushing, irrigation, cooling equipment makeup, ornamental water features, and clothes washing. Now you may think: clothes washing?! Yes! In fact, the city of San Francisco requires recycled water to be used for clothes washing, and other jurisdictions may soon be on the way.

Usually, the most straightforward option is the flush fixtures. This is because flush fixtures and clothes washers operate daily and on a predictable schedule, generally aligned with the pattern for wastewater supply.

Irrigation and cooling equipment makeup are also great options because they have the potential to use a very large volume of water, but the seasonality of the water demand will need to be considered. If recycled water is used solely cooling tower makeup or solely irrigation, an optimization analysis will determine how to size the treatment system for optimal payback while covering the most amount of the seasonal peak water demand as possible.

Local/state regulations

It’s important to conduct research or speak with an expert to determine what regulations exist in your area governing wastewater reuse. You may find that some level of wastewater reuse is required. You may also find that while it may not be required, attractive grants and incentives exist to motivate projects to install wastewater reuse. Connect with us if you’re interested in finding out what grants or incentives may be available in your area.

Here are some examples of U.S. cities with current wastewater reuse regulations:

San Francisco: requires most new construction over 100,000-square-feet to install wastewater reuse.
New York City: offers 25% reduction in utility fees if wastewater reuse systems cut the building’s water use by 25%, and a 75% wastewater fee discount for properties that discharge less than 25% of their total annual wastewater flow to the city’s sewer system.
Austin: requires all cooling towers in multifamily and commercial buildings to be supplied with non-potable water from an onsite reuse system and the city requires most developments over 250,000-square-feet to recycle greywater or rainwater and condensate.

Even if wastewater reuse is not required or incentivized, local jurisdictions may very likely have rules and regulations governing the design and implementation of onsite reuse systems. Engaging regulators early in the process will streamline the process and ensure that the system is designed to and operating in accordance with all local and national standards. Epic Cleantec can help with this process.

Sustainability goals

Is your project targeting LEED Certification? How about the Living Building Challenge? These certifications can enhance a building’s reputation, property value, and user satisfaction. It’s also a great way to market your building to future residents or tenants!

An onsite wastewater reuse system has the potential to earn a project up to 25 LEED points. The graph below shows the huge benefit that an onsite wastewater treatment system can add to a LEED project. One thing to note is that this estimate is based on a project in California and points may vary between regions and/or sites.

Your project can earn up to 25 LEED points through full resource recovery

Type of construction

Is your project a retrofit or new construction? Either can work, but there are important parameters to keep in mind for a retrofit. Is the plumbing infrastructure for recycled water piping installed, or can be installed without cost prohibitive demo? Does the site have room for the equipment and tanks, and can they be installed without prohibitive demo? It is helpful to speak with a professional engineer to determine whether an installation is feasible for all types of construction.

New construction projects provide flexibility in the design and scope if onsite reuse is considered early on. We serve as the single point of contact to walk you through the entire process, from design to installation and permitting of the system.

Water reuse feasibility checklist

Use this checklist to evaluate whether onsite water reuse may be a good fit for your project. In general, strong candidates have enough water demand to justify the system, clear non-potable reuse applications, favorable local utility rates or incentives, and enough space to accommodate treatment equipment and storage. Factors like project size, location, end uses, regulations, sustainability goals, and construction type are key considerations for onsite reuse feasibility.

Building type and project size

Does the project have consistent daily water use?
Is the building large enough to generate meaningful water and sewer savings?
Is the project a multifamily, mixed-use, commercial, hospitality, campus, or other high-use property?
Is the project new construction, where recycled water piping and system infrastructure can be planned early?
If it is a retrofit, can the existing plumbing and infrastructure support a reuse system without cost-prohibitive demolition?

Strong fit: Large buildings, new construction projects, and projects with predictable daily water demand are often better candidates for onsite water reuse.

Water balance

How much water does the building use annually?
How much wastewater does the building generate?
What percentage of that wastewater could be captured, treated, and reused?
Are water supply and reuse demand relatively balanced throughout the year?
Would the system reduce both potable water purchases and sewer discharge costs?

Strong fit: Projects with enough wastewater supply and enough non-potable demand to reuse a meaningful volume of water onsite.

Location

What are the local water and sewer utility rates?
Are rates high enough that reducing municipal water use could create meaningful savings?
Are there local or state onsite reuse requirements?
Are grants, rebates, or incentives available?
Does the project sit in a water-stressed region or a market where sustainability and resilience are priorities?

Strong fit: Projects in areas with high utility rates, water scarcity concerns, reuse mandates, or incentives that can improve ROI.

Space and infrastructure

Is there room for treatment equipment, tanks, controls, and maintenance access?
Can equipment be placed in a basement, mechanical room, garage, utility area, or other available space?
Can the system be integrated without disrupting building operations or design goals?
Is there enough space for safe access, monitoring, and ongoing maintenance?
For retrofits, can recycled water piping be added without major structural or plumbing constraints?

Strong fit: Projects with dedicated space for equipment and enough design flexibility to integrate tanks, treatment systems, and recycled water piping.

End uses for recycled water

Can recycled water be used for toilet or urinal flushing?
Is there demand for irrigation?
Does the building use cooling equipment that requires makeup water?
Are laundry systems, ornamental water features, or other non-potable applications available?
Are these end uses consistent enough to support a reliable payback period?

Strong fit: Projects with steady non-potable uses, especially toilet flushing, laundry, and cooling tower makeup, because they can create regular demand for treated water. Epic notes that end uses such as flushing, irrigation, cooling equipment makeup, ornamental water features, and clothes washing may be permitted depending on local regulations.

Discuss your next project with our team

While these considerations are not comprehensive of all the necessary drivers, they should serve as a good starting point to think about for your next project. One of the biggest drivers is location, and factors such as local climate, regulations and utility rates make an impact in ROI. Interested in learning more? Read more about how we determine ROI for projects.

The information covered here represents only a tiny fraction of the information on onsite wastewater reuse systems. Let’s discuss your upcoming project to see if onsite water reuse is right for it!

Ready to reduce annual water/sewer costs and enable resilience in your next project?

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Frequently asked questions about onsite water reuse systems for multifamily properties

Are onsite water reuse systems a good fit for multifamily properties?: Yes, multifamily properties can be strong candidates for onsite water reuse because they often have consistent daily water use and reliable non-potable water demand. Recycled water may be used for applications such as toilet flushing, irrigation, laundry, or cooling systems, depending on local regulations and project design.
What makes a multifamily project suitable for onsite water reuse?: A good candidate typically has a strong water balance, meaning the property generates enough wastewater and has enough approved non-potable uses to reuse that water onsite. Building size, location, utility rates, available space, and local permitting requirements all affect whether a system is technically and financially feasible.
Can onsite water reuse help multifamily properties lower operating costs?: Yes. By treating and reusing water onsite, multifamily buildings can reduce the amount of potable water they purchase and may also lower sewer discharge costs. The total savings depend on the property’s water use, local water and sewer rates, system size, and annual operating costs.
Is onsite water reuse easier to add during new construction or as a retrofit?: Onsite water reuse is often easier to incorporate during new construction because recycled water piping, equipment space, storage tanks, and end uses can be planned from the start. Retrofits may still be possible, but they require a closer look at existing plumbing, available space, installation complexity, and project economics.