Originally published February 6, 2024. Updated October 2026.
Effective greenhouse water management requires more than delivering irrigation water to the crop. Source-water quality, irrigation strategy, drain-water collection, treatment, nutrient management, storage, and reuse all affect the performance and efficiency of the complete water process.
The Greenhouse Water Management Guide, developed by GRODAN and Priva, provides a detailed overview of these topics for commercial greenhouse production.
The guide remains a useful industry reference for growers, designers, and technical teams evaluating irrigation performance, drain-water recycling, and strategies for reducing water and nutrient losses.
Resource note: This guide was authored and published by GRODAN and Priva. Integrated Water Process is providing access to the resource for educational purposes and did not author the publication.
View the Water Management Guide
What Does the Guide Cover?
The guide approaches greenhouse water management as a connected process rather than a collection of isolated equipment decisions.
Topics include:
- Primary water quality
- Irrigation management
- Root-zone water management
- Irrigation-system design considerations
- Drain-water collection
- Drain-water cleaning and disinfection
- Nutrient management
- Water recycling and reuse
- Monitoring and control
- Strategies for reducing water and fertilizer losses
Start With Source-Water Quality
The quality of the incoming water establishes the starting point for the entire irrigation process.
Water sources may include:
- Municipal water
- Well water
- Surface water
- Rainwater
- Reverse osmosis permeate
- Recovered condensate
- Reclaimed irrigation water
Each source can have different characteristics that influence treatment, nutrient formulation, equipment selection, and long-term system performance.
Parameters such as alkalinity, hardness, sodium, chloride, electrical conductivity, pH, and microbiological conditions should be understood before treatment or fertigation equipment is selected.
Integrated Water Process provides hydroponic water testing and analysis to help growers establish that baseline.
Manage Irrigation Around the Root Zone
Water management does not end when irrigation reaches the growing media.
Irrigation volume, frequency, timing, substrate characteristics, crop demand, environmental conditions, and drainage strategy all influence the conditions surrounding the root system.
Precision irrigation requires defined operating targets and acceptable deviations rather than simply applying a fixed volume of water.
Useful measurements can include:
- Irrigation volume
- Drain volume
- Electrical conductivity
- pH
- Substrate moisture
- Water temperature
- Flow rate
- Pressure
These measurements help growers understand whether irrigation is performing consistently across the production system.
Design the Irrigation System Around Defined Requirements
Reliable water management depends on the physical irrigation system.
Pumps, tanks, filters, valves, distribution piping, emitters, fertigation equipment, and controls must be coordinated around the required flow and pressure.
Important design considerations include:
- Peak irrigation demand
- Number of simultaneous irrigation zones
- Required pressure at the point of use
- Emitter flow characteristics
- Filtration requirements
- Storage capacity
- Fertigation strategy
- Controls and automation
- Drainage and recovery
Learn more about commercial hydroponic irrigation systems.
Drain Water Is a Resource
Drain water from hydroponic production can contain both water and residual nutrients that may have value if the stream can be safely and reliably recovered.
Rather than automatically sending drain water to waste, growers can evaluate whether it can be:
- Collected
- Filtered
- Disinfected
- Blended
- Adjusted for nutrient balance
- Returned to the irrigation process
The feasibility of reuse depends on water quality, crop requirements, system configuration, sanitation strategy, and operational risk.
Treatment Should Match the Reuse Objective
Recovered water should be characterized before treatment equipment is selected.
Potential treatment processes may include:
- Screen filtration
- Disc filtration
- Media filtration
- Cartridge filtration
- Ultraviolet disinfection
- Oxidation
- Membrane treatment
- Other sanitation or polishing processes
The correct treatment train depends on what needs to be removed and what finished-water quality is required.
Learn more about commercial hydroponic water reclamation systems.
Nutrient Management Is Part of Water Reuse
Reclaimed irrigation water may contain residual fertilizer salts. Reuse therefore requires more than simply disinfecting the water and returning it to the irrigation system.
Growers should consider:
- Electrical conductivity
- Individual nutrient concentrations
- Sodium and chloride accumulation
- pH
- Alkalinity
- Blend ratios
- Crop sensitivity
- Changes in nutrient balance over time
Water reuse works best when water quality, nutrient management, treatment, and fertigation are considered together.
Measure Before You Manage
Monitoring is essential to understanding whether the water process is performing as intended.
Depending on the facility, useful measurements may include:
- Incoming water volume
- Irrigation volume
- Drain volume
- Recovered water volume
- pH
- Electrical conductivity
- Flow
- Pressure
- Tank level
- Water temperature
- Treatment-system performance
These measurements can also support a facility water balance and help identify where water is being consumed, reused, or discharged.
Water Reuse Requires a System-Level Approach
A successful recycling strategy depends on coordination between several parts of the facility.
For example, recovered water storage must have enough capacity to manage variable drain flow. Treatment equipment must be sized for the required throughput. Fertigation must account for nutrients already present in the reclaimed stream. Controls must determine when recovered water can be reused and when it should be rejected or diverted.
These interfaces are why water reuse should be planned as part of the complete water process.
Total Water Management
The principles discussed in the GRODAN and Priva guide align with the Integrated Water Process approach to Total Water Management.
We evaluate water from the source through treatment, storage, pumping, fertigation, irrigation, drainage, recovery, treatment for reuse, and final discharge.
The goal is to define how each part of the system contributes to reliable crop production while reducing unnecessary water use and improving visibility into system performance.
Explore our hydroponic water engineering services and commercial water system solutions.
About the Greenhouse Water Management Guide
The Greenhouse Water Management Guide was published by GRODAN and Priva as an industry resource covering greenhouse irrigation and water recycling practices.
Readers should be aware that the publication dates from 2016. Some regulatory references, economic examples, technology descriptions, and regional assumptions may therefore reflect conditions in Europe at the time of publication rather than current requirements in the United States.
Technical concepts related to irrigation management, drain-water recovery, treatment, nutrient management, and water reuse remain useful, but project-specific decisions should be based on current water quality, applicable regulations, equipment capabilities, and facility requirements.