Household

Washing dishes by hand (one equivalent load)

Tiskaaminen käsin (yksi koneellinen vastaava määrä)

4.3

Truecost score

Data confidence: MEDIUM

Highly behavior-dependent. Carbon and water estimates based on 'typical' European behavior but individual variation is enormous.

Hand washing dishes with a running tap produces ~1.1 kg CO₂e and uses ~50 liters of water per equivalent load — more than double a dishwasher's eco mode.

Did you know? The two-basin hand washing method (wash in hot, rinse in cold) is 18% lower in emissions than a dishwasher. But most people wash under a running tap — the worst option.

Transparent calculation

How was this number determined?

The Truecost score is calculated from absolute physical values. Each row below shows the measured value, how it was normalized, and where it comes from.

Dimension	Absolute value	Score 100 =	Normalized	Weight	Weighted	Confidence
Carbon Emissions	1.1 kg CO₂e	9.5 kg CO₂e	11.58	×0.35	4.05	MEDIUM
Water Consumption	50.0 liters	3840 liters	1.3	×0.2	0.26	MEDIUM
Land Use	0.0 m²·year	51 m²·year	0.0	×0.2	0.00	HIGH
Waste	0.002 kg	5 kg	0.04	×0.15	0.01	HIGH
Toxicity	0.2 µDALY	162 µDALY	0.12	×0.1	0.01	LOW
Truecost score (weighted sum)					4.3

Share of your annual planetary budget

Carbon Emissions 0.12%

Water Consumption 0.01%

Waste <0.01%

Toxicity <0.01%

Source data by dimension

Where do the absolute values come from?

Carbon Emissions

MEDIUM

Porras et al. (2020, U. Michigan): typical hand washing (running tap) 5,620 kg CO₂e over 10 years at 4 loads/week ≈ 2,080 loads → ~2.7 kg CO₂e/load. However, this assumes US gas water heating. With European electric heating and moderate tap habits: ~1.1 kg CO₂e/load. Two-basin method: ~0.8 kg CO₂e/load.

Porras et al. (2020): A guide to household manual and machine dishwashing through a life cycle perspective — Environmental Research Communications

Highly variable depending on behavior. Running tap: 1.5-2.7 kg. Moderate use: ~1.1 kg. Two-basin method: ~0.8 kg. Using 1.1 as 'typical European' estimate.

Water Consumption

MEDIUM

Porras et al. (2020): typical hand washing uses 40-100 L per load with running tap. ENERGY STAR estimates up to 87 L (23 gallons). European moderate estimate: ~50 L. Two-basin method: ~20 L.

Porras et al. (2020): U. Michigan dishwashing LCA
ENERGY STAR (2024): Dishwasher vs hand washing comparison

Enormous variation. Some people use 20 L, others 100 L. 50 L is a moderate estimate for typical running-tap behavior.

Land Use

HIGH

No significant land use

Negligible.

Waste

HIGH

Dish soap bottle (~500 mL, ~30g plastic) lasts ~100 loads → ~0.3g plastic + ~5 mL soap per load. Minimal waste.

Very minor waste stream.

Toxicity

LOW

Dish soap contains surfactants (SLS/SLES), fragrances, preservatives. Lower concentration than machine detergent but direct skin contact. Aquatic toxicity from greywater discharge. Rough estimate ~0.2 µDALY.

Golsteijn et al. (2015): Life cycle studies for household detergent products — Environmental Sciences Europe

Varies enormously by product. Eco-friendly soaps significantly lower toxicity.

Comparisons

Over 2x the emissions of a dishwasher eco cycle (0.47 vs 1.1 kg CO₂e)
5x more water than a dishwasher (50 vs 10 liters)
Two-basin method reduces emissions to 0.8 kg — better than a machine

Methodology

Based on Porras et al. (2020) University of Michigan lifecycle study. Adjusted for European electric water heating. Uses 'moderate running tap' scenario.

Sources

Porras et al. (2020): A guide to household manual and machine dishwashing — Environmental Research Communications
ENERGY STAR (2024): Dishwasher vs hand washing comparison