Most developers don’t get into real estate to think about wastewater. But as utility costs rise and sustainability expectations tighten, the communities winning the most attention—and the highest valuations—are those that have built resilience into their water systems. 

At the center of that conversation is a simple, high-impact question: what happens to your wastewater?

Increasingly, the answer is on-site water reuse. 

Specifically, decentralized water reuse systems powered by membrane bioreactor (MBR) technology are giving residential communities the ability to reclaim and reuse their treated wastewater for non-potable water applications like irrigation, cooling, and toilet flushing. This shift offers direct financial benefits to developers and long-term returns for HOAs, while supporting water conservation and regional water resilience.

Turning Wastewater Into a Financial Asset

In many communities, water and sewer charges are already a top line item in HOA budgets—and that’s before you factor in the premium pricing tiers some water utilities apply to high summer usage. Irrigation water alone can account for more than half of a community’s total annual potable water demand, particularly in high-end neighborhoods with shared green spaces, pools, or ornamental landscaping.

By reclaiming recycled water onsite, developers and HOAs can offset that potable water use demand with a steady, reliable supply of reclaimed water.

For a 100-home community, this can translate into millions gallons per year of recovered water. When municipalities are charging $6–$10 per thousand gallons for both drinking water and sewer discharge, that’s a direct savings of tens of thousands of dollars annually—without changing a single resident’s behavior.

Putting That Asset to Work

So, now that your development firm has projected cash savings, what’s the longer-term goal for your newfound water reuse system? 

1. Subsurface Irrigation for Common Areas

In master-planned communities, the largest non-potable water demand often comes from irrigating shared landscapes: green belts, HOA-maintained lawns, medians, and parks. 

MBR-treated water, with consistently low turbidity and pathogen levels, is ideal for subsurface drip irrigation. This method reduces evaporation loss and minimizes aerosol concerns, making it a safe and sustainable solution in residential zones.

2. Irrigation for Private Yards

Developments with dual-plumbed lots can route recycled water to individual homes for lawn and garden irrigation. This not only saves potable water but can also help homeowners maintain green lawns during drought restrictions, which is a significant selling point in water-stressed regions like California, Arizona, or Texas.

3. Toilet and Urinal Flushing in Dual-Plumbed Buildings

MBR systems can supply reclaimed water for indoor non-potable uses, particularly in townhomes, condos, or mixed-use buildings designed with dual plumbing. Flushing toilets with reclaimed water can reduce potable demand significantly. 

4. Cooling Towers and HVAC Systems

Larger residential developments with clubhouses, gyms, or shared commercial facilities often operate HVAC systems with evaporative cooling towers. Treated wastewater can be routed to these systems as makeup water, replacing thousands of gallons of potable water per day.

5. Fire Suppression Storage

In remote or low-pressure areas, developments may require additional fire suppression volume. MBR-treated water stored in non-potable tanks can supplement fire protection infrastructure (pending local code), reducing reliance on potable water supply for emergency purposes.

6. Dust Control and Construction Use

During construction phases, onsite water reuse systems can be used for dust suppression, soil compaction, or wash-down applications—offsetting demand from hydrants or water trucks. This helps conserve potable supply and can be a visible sustainability gesture to local authorities.

7. Augmenting Decorative Water Features

In some projects, reclaimed water has been used to feed artificial lakes, ponds, or fountains, features that can enhance curb appeal without drawing on municipal water supply. When designed appropriately, this use meets water reuse regulations aesthetics, and conservation goals.

The Technology Behind the Benefit

Membrane bioreactors (MBRs) are ideal for onsite wastewater reuse in residential settings because they pair biological treatment with membrane filtration in a compact, closed-loop system. This process meets high water quality standards

At IWS, we typically size these systems based on peak daily flows, average nutrient loading, and the site’s reuse goals. Systems are designed to meet or exceed Title 22 requirements, with effluent turbidity consistently below 0.2 NTU—no tertiary polishing or reverse osmosis required.

These systems operate using a highly concentrated mixed liquor suspended solids (MLSS) environment, typically 8,000–12,000 mg/L. This allows for significantly reduced tank volumes, a smaller system footprint, and much lower sludge yields. 

The membranes retain all solids while allowing clean water to pass, producing effluent that is colorless, odorless, and safe for immediate reuse in subsurface irrigation loops, holding tanks for non-potable distribution, or even cooling towers if designed appropriately.

Implementation in Residential Developments

One of the most common concerns we hear from developers is about the physical integration of these systems. Where do they go? Will homeowners notice them?

In most cases, MBR systems are installed in prefabricated, partially buried concrete vaults, sited away from high-traffic residential zones. This might be behind a service building, maintenance yard, or landscaped buffer zone. With enclosed blower cabinets, odor control scrubbers, and remote telemetry via SCADA systems, these facilities operate quietly and cleanly. From a visual or operational standpoint, they’re practically invisible once in place.

More importantly, because the systems are modular and prefabricated, they can be delivered and installed late in the construction sequence—allowing developers to stay on schedule and avoid large upfront site disruption.

Marketability and Homeowner Buy-In

The presence of onsite water reuse infrastructure may not be a visible marketing feature like a clubhouse or trail network, but it pays real dividends in long-term perception and utility savings. Buyers increasingly care about sustainability, particularly in regions where water restrictions are common. Communities that can irrigate during droughts, that offer lower monthly HOA fees, and that demonstrate true independence from strained municipal systems have a compelling story to tell.

Developments that integrate dual-plumbed buildings or smart irrigation systems can directly tie homeowner savings to reuse strategies. And in many cases, local governments offer density bonuses, fee reductions, or expedited permitting for projects that include advanced water recycling infrastructure.

Long-Term Maintenance and HOA ROI

Post-buildout, most MBR systems are transitioned to HOA or utility ownership. That transition is often supported through tailored O&M programs that may include membrane cleaning, sludge hauling, instrumentation checks, and annual optimization reviews.

Because MBR systems maintain high-quality effluent even under load variability, they’re often more stable than older technologies like lagoons or sequencing batch reactors (SBRs), particularly in communities with seasonal occupancy shifts. SCADA-based controls also allow remote monitoring and diagnostics, reducing the need for full-time onsite operators while ensuring compliance and early fault detection.

This stability translates into long-term budget control. No surprise hauling costs. No massive spikes in energy use. Just a known quantity with predictable operating costs, which is exactly the kind of infrastructure HOAs prefer to manage.

A New Tool in the Developer’s Toolkit

For developers, onsite reuse systems expand what’s possible. They reduce infrastructure dependencies, lower utility tie-in costs, and unlock buildable land that may otherwise have been sidelined due to sewer access issues or effluent discharge restrictions. For HOAs, they offer cost control, sustainability, and a forward-looking asset that adds real, tangible value to the community.

In an environment where land costs are rising and buyers are looking for more than square footage, integrating an MBR-based reuse strategy is a market advantage.