How Much Water Does a Hydroponic System Use?

Hydroponic systems are known for being very water-efficient. They often use up to 90% less water than traditional farming. This is due to their design that allows for water reuse.

The actual water usage depends on several factors. These include the type of crop, the hydroponic system design, environmental conditions, and the plant's growth stage.


How Much Water Does a Hydroponic System Use? - Image

Overall Water Efficiency

  • Reuse Benefits:
    In a recirculating hydroponic system, the nutrient solution is reused all the time. Most water loss comes from evaporation, transpiration, and minor leaks rather than from the system’s water delivery itself.

  • Water Savings:
    Hydroponic systems can use up to 90% less water than traditional soil-based farming. This is because water goes straight to the plant roots and is reused during the growing process. 

Analyze Plant Variety and Growth Stages

Different types of plants have varying water and water flow requirements, and these needs change during their growth cycle.
Here’s a closer look at a few common categories grown in water-based systems in the United States:

Leafy Greens (e.g., Lettuce, Spinach, Kale)

Seedling Stage (Weeks 0–2):

  • Water Use: Approximately 200–300 mL per plant per day
  • Notes: Young plants require a gentle, consistent moisture level. Over-watering is avoided to prevent damping-off disease.

Vegetative Stage (Weeks 3–5):

  • Water Use: Approximately 400–600 mL per plant per day
  • Notes: As leaves expand and light-converting activity increases, so does water uptake. Efficient nutrient uptake is critical during this rapid growth phase.

Mature Stage (Weeks 6–8 and beyond):

  • Water Use: Approximately 600–800 mL per plant per day
  • Notes: At maturity, transpiration rates peak, especially under high light conditions from advanced grow lights. The reusing system replenishes moisture while minimizing overall water loss.

Fruiting Crops (e.g., Tomatoes, Peppers, Cucumbers)

Seedling Stage (Weeks 0–2):

  • Water Use: Approximately 200–300 mL per plant per day
  • Notes: Similar to leafy greens, young fruiting plants are delicate and require lower water volumes.

Vegetative Stage (Weeks 3–5):

  • Water Use: Approximately 1–1.5 liters per plant per day
  • Notes: The larger plant size and increased leaf area lead to higher transpiration rates.

Fruiting Stage (Weeks 6–10 and beyond):

  • Water Use: Approximately 1.5–2+ liters per plant per day
  • Notes: When plants start to grow fruit, they need more water. This is due to the needs of fruit growth and increased overall size. It is essential to maintain constant nutrient levels during this period of high demand.

Herbs (e.g., Basil, Mint, Cilantro)

Seedling Stage:

  • Water Use: Approximately 150–250 mL per plant per day
  • Notes: Herbs generally have lower water needs compared to larger fruiting crops.

Vegetative to Mature Stages:

  • Water Use: Approximately 300–500 mL per plant per day
  • Notes: Water consumption increases gradually, and efficient water recycling further minimizes overall usage.

System Losses and Recapture

Evapotranspiration Losses:

Even in a closed-loop system, some water is lost. This happens through evaporation from the reservoirs and transpiration from the plants. These losses typically account for about 5–10% of the total water cycled through the system per day.

Seasonal and Environmental Impacts:

In the United States, indoor and greenhouse operations may experience varying water needs depending on ambient temperature and humidity. For example, in summer or warmer areas, evaporation rates can go up. This may slightly increase the need for water.

Practical Implications for U.S. Hydroponic Growers

Optimizing Water Use:

Many U.S. hydroponic operations employ sensors and automated control systems to monitor moisture levels in real time. This lets growers change water delivery based on the plant's growth stage and weather. This helps reduce waste.

Economic and Environmental Benefits:

Using less water not only saves money but also helps sustainable farming. This is especially important in areas with water shortages or strict environmental rules.

Hydroponic systems in the United States typically use water efficiently. For example, leafy greens may need 200 to 800 mL of water per plant each day. In contrast, fruiting crops like tomatoes and peppers might require 1 to over 2 liters per plant daily during peak times. With water reuse and careful monitoring, actual water losses are minimized, making hydroponics an attractive, sustainable alternative to traditional soil-based agriculture.