Water Reuse for Irrigation: Benefits, Challenges, and Soil Management

Water is one of our most valuable natural resources, and protecting supplies of potable drinking water is becoming increasingly important for communities across the United States.

Municipalities are continually exploring ways to conserve freshwater resources, reduce treatment costs, and make better use of reclaimed wastewater and treated effluent.

One increasingly important strategy is water reuse.

How Communities Are Reusing Treated Wastewater

Instead of discharging treated wastewater and allowing that resource to go unused, communities can evaluate opportunities to reuse effluent for beneficial purposes.

Depending on local regulations and treatment requirements, reclaimed water may be used for:

Golf course irrigation
City parks and landscaping
Sports complexes
Streetscapes
Residential developments
Agricultural irrigation
Industrial applications
Certain potable reuse programs

Wichita Falls, Texas, for example, has used advanced water reuse strategies as part of its efforts to protect municipal water supplies.

Other communities use treated wastewater primarily for landscape and irrigation applications, reducing the amount of potable water needed for non-drinking purposes.

Using Purple Pipe for Reclaimed Water Irrigation

Reclaimed water distribution systems are commonly identified by purple pipe.

When economically and technically feasible, dedicated reuse-water infrastructure allows communities to deliver treated effluent to parks, golf courses, commercial landscapes, and other irrigation users without relying on potable water.

This can help municipalities conserve higher-quality drinking water for uses where potable water is truly necessary.

Benefits of Reclaimed Wastewater for Irrigation

Using treated effluent for irrigation can provide several potential benefits.

Conserving Potable Water

One of the greatest benefits of reclaimed water irrigation is reduced demand for treated drinking water.

Using potable water to irrigate large turf areas can increase water treatment and distribution demands. Reclaimed water provides an alternative source for applications where drinking-water quality is not required.

Recycling Plant Nutrients

Treated wastewater may contain nutrients such as nitrogen and phosphorus that can benefit turf, landscaping, and certain agricultural crops.

Depending on water quality and plant requirements, these nutrients may supplement a portion of a landscape's fertilizer needs.

Creating Value from Treated Effluent

Reclaimed wastewater can become a valuable municipal resource rather than simply a discharge stream.

Utilities may be able to charge qualified customers for reuse water, potentially helping offset some of the costs associated with treatment, distribution, and reuse infrastructure.

Supporting Sustainable Water Management

Reusing treated wastewater can reduce demand on freshwater supplies while promoting a more circular approach to municipal water management.

Challenges of Reclaimed Water Programs

Although water reuse offers significant opportunities, municipalities must also consider several practical challenges.

Public Perception

Public acceptance can be one of the greatest obstacles to implementing a reclaimed water program.

Clear communication and public education are important for explaining:

How reclaimed water is treated
Where it can safely be used
How reuse systems are monitored
Why water conservation is important
How reclaimed water differs from potable drinking water

Education can help communities better understand the role of recycled water in long-term water management.

Infrastructure Costs

Installing purple pipe and reclaimed water distribution systems requires significant infrastructure investment.

Communities should compare installation costs with potential long-term savings in potable water production, irrigation expenses, and resource conservation.

Water Rights and Regulations

Water reuse requirements vary by state and local jurisdiction.

Water rights, groundwater recharge requirements, discharge permits, and reuse regulations may all affect whether treated effluent can be redirected for irrigation.

Municipalities should evaluate these requirements before developing a reuse program.

Managing Sodium and Salts in Reclaimed Water

One of the most important considerations when using treated wastewater for irrigation is salinity.

Depending on the wastewater source and treatment process, reclaimed water may contain elevated concentrations of sodium and other dissolved salts.

Repeated irrigation with high-salinity water can cause salts to accumulate in soil over time.

Excess sodium may negatively affect:

Soil structure
Water infiltration
Root development
Nutrient availability
Soil microbial activity
Plant health

For this reason, reclaimed irrigation water should be regularly tested for salinity, sodium, and other important water-quality parameters.

How Sodium Can Affect the Plant Root Zone

Excess sodium can disrupt soil aggregation and reduce the movement of water and air through the root zone.

When soil structure declines, plants may develop smaller or weaker root systems.

Reduced root development can make it more difficult for plants to access water and nutrients, potentially increasing their vulnerability to heat and drought stress.

Some landscape plants may also be particularly sensitive to saline irrigation water. Trees and shrubs exposed to reclaimed-water overspray may develop leaf or needle damage when salt concentrations become excessive.

Reducing Salt Inputs at the Source

Municipal education programs can also help reduce the amount of salt entering wastewater collection systems.

Household water softeners can be a significant source of sodium in some wastewater systems.

Communities may encourage residents to evaluate:

Whether a water softener is necessary
Whether the system regenerates only when needed
How frequently regeneration occurs
Whether softening can be limited to specific household uses
Whether equipment is operating efficiently

Reducing unnecessary salt inputs can improve wastewater quality before the water reaches the treatment plant.

Supporting Soil Health When Using Reclaimed Water

Healthy soil can help landscapes tolerate some of the challenges associated with reuse water irrigation.

Before developing a soil-management program, growers and landscape managers should consider testing:

Soil organic matter
pH
Electrical conductivity
Sodium
Calcium
Magnesium
Cation exchange capacity
Nutrient availability

These measurements provide valuable information about how reclaimed water is affecting the soil over time.

The Importance of Soil Organic Matter

Maintaining adequate soil organic matter can support soil aggregation, microbial activity, nutrient cycling, and water movement.

If soil testing indicates low organic matter, managers may consider incorporating appropriate organic amendments and other soil-building practices.

Biological soil amendments, organic acids, humic substances, and other compatible products may also be incorporated into a broader soil-management strategy based on site conditions.

Developing a Reuse Water Soil Management Program

Successful reclaimed-water irrigation requires more than simply changing the source of irrigation water.

A long-term program should consider:

Irrigation water quality
Soil salinity and sodium
Organic matter levels
Nutrient inputs
Drainage
Irrigation frequency
Plant salt tolerance
Soil microbial health
Fertilizer requirements

Regular water and soil testing can help landscape managers adjust their programs before sodium or nutrient accumulation becomes a larger problem.

Making Reclaimed Water a Valuable Resource

Reclaimed wastewater can provide communities with an important tool for water conservation, irrigation, and sustainable resource management.

When managed correctly, treated effluent can reduce demand for potable water, recycle valuable nutrients, and provide municipalities with an additional water resource.

At the same time, successful reuse programs must account for water quality, salinity, soil health, infrastructure costs, regulations, and public education.

BioLynceus® provides soil and plant management products designed to support healthy soils and landscapes irrigated with reclaimed water.

For more information about BioLynceus® products for reuse-water irrigation and soil management, contact us at (970) 586-3391 or sales@biolynceus.net.

Wastewater Reuse and its Impact on the Environment