Water Benchmarks

Water benchmarks establish reference points for rating food products based on their water scarcity impact.

Benchmark Methodology

Water impact is measured as scarcity-weighted water consumption. The benchmark was calculated on the same data basis as the climate benchmark.

Data Sample

Parameter	Value
Businesses analyzed	150
Purchases analyzed	>3.5 million
Data period	2019-2021
Geographic focus	Primarily Switzerland

Benchmark Value

91.56 liters scarce water per Daily Food Unit (DFU)

This is the average scarcity-weighted water footprint across all analyzed food purchases.

Distribution Pattern

Unlike CO₂ values (which follow a more normal distribution), water footprint values are highly exponential. A few products from water-scarce regions (almonds, cashews, olives) have extremely high values (>5,000 L/DFU), while most products are well below average.

The 50% Reduction Goal

The rating system is designed around a key environmental target: reducing our dependency on scarce water by 50%.

How It Works

Analysis of the cumulative distribution reveals that this goal can be achieved by avoiding extreme outliers:

Threshold	Cumulative DFU	Cumulative Water	Result
Products below 1,059.85 L/DFU	6,404,682	293,210,216 L	45.78 L/DFU

By only consuming products with less than 1,059.85 L/DFU, the cumulative water footprint is exactly half the average (45.78 L vs 91.56 L).

Key Insight

Products with a higher water footprint than average can still receive a reasonable rating because avoiding extreme outliers achieves the 50% reduction goal. The focus is on eliminating the worst offenders, not penalizing everything above average.

Rating Thresholds

The A-E rating system is based on scientifically derived thresholds:

Threshold	Water/DFU	Multiplier	Description
A vs B	91.56 L	1× (average)	Optimal scarce water consumption. Products below average guarantee reduced dependency on scarce water.
B vs C	183.12 L	2× average	Still very low consumption of scarce water.
C vs D	366.24 L	4× average	Substantially higher consumption (at least 4× average).
D vs E	1,059.85 L	Cumulative threshold	Critical threshold. Products above this value prevent achieving the 50% reduction goal.

Rating Interpretation

Rating	Description	Recommendation
A	Below average	Supports 50% reduction goal
B	Up to 2× average	Low impact, good choice
C	2-4× average	Moderate impact
D	4× to threshold	High impact, reduce consumption
E	Above threshold	Very high impact, avoid when possible

High-Impact Products

Products with extremely high water footprints (>5,000 L/DFU) typically come from water-scarce regions:

Product	Typical Origin	Water Impact	Notes
Almonds	California, Spain	Very High	Severe water stress regions
Cashews	Vietnam, India	Very High	Irrigation-intensive
Olives	Mediterranean	Very High	Often from stressed aquifers
Avocados	Mexico, Chile	High	Water-intensive cultivation

Regional Comparison Example

The same product can have vastly different water impacts depending on origin:

Product	Origin	Irrigation Need	Scarcity Footprint
Tomato	Switzerland	Baseline	1×
Tomato	Spain	44× Swiss tomato	2,400× Swiss tomato

This dramatic difference occurs because Spanish tomatoes require extensive irrigation in a water-stressed region, while Swiss tomatoes rely more on rainfall.

Water Stress Index (WSI)

The scarcity weighting uses the Water Stress Index methodology:

WSI Range	Stress Level	Description
0.01 - 0.10	None	Water abundant
0.10 - 0.50	Moderate	Some seasonal stress
0.50 - 0.90	Severe	Significant water scarcity
≥ 0.90	Extreme	Critical water shortage

Data Sources

Water footprint calculations use:

• Scherer & Pfister (2016b) — Water scarcity footprint data for 142 products across 162 countries
• Pfister et al. (2009) — Water Stress Index methodology
• Global models — 6 models for river discharge, 4 for groundwater recharge, 6 for precipitation, 3 for water use
• Spatial resolution — 10×10 km grid

Global Context

Understanding why water scarcity matters:

Statistic	Value
People without clean water access	663 million
Agriculture share of freshwater use	70%
Global average WSI for food production	0.51 (moderate-high stress)
Average person's local WSI	0.32

The disconnect between where food is produced (often water-scarce regions) and where it is consumed creates a "virtual water" transfer that strains global water resources.

Swiss-Specific Insights

Products with high water footprints commonly consumed in Switzerland:

• Olives and olive oil
• Nuts (almonds, cashews, walnuts)
• Chocolate and cocoa
• Coffee
• Milk products (due to feed)
• Rice
• Beef

These products often come from water-stressed regions, making origin selection critical for reducing water impact.

See Also

• Water Footprint Rating — Understanding water ratings
• Climate Benchmarks — CO₂ benchmark methodology
• Methodology Overview — LCA methods