# How do I calculate the carbon footprint of an RO water purifier?

Canonical: https://senseible.earth/answers/ro-water-purifier-carbon-footprint-per-unit

List the parts by weight: plastic body, membrane, filters, pump, adapter and tank, with supplier figures. Add the plant's moulding and assembly electricity per unit and packing. Use-phase electricity is a separate figure, stated with its assumptions.

## Materials

- ABS or PP body and tank by weight.
- RO membrane, sediment and carbon cartridges.
- Booster pump, solenoid valve, adapter, PCB and UV lamp.

## Making

- Moulding of the body, if done in house.
- Assembly, leak and TDS testing.
- Carton, thermocol or moulded pulp inserts.

## Per unit

Report cradle to gate per unit. If a buyer wants use phase, state the daily litres, hours and years assumed.

## Worked example: purifier assembly per unit (one month)

- Electricity: 30,000 kWh x 0.710 = 21,300 kg CO2
- Units passed: 20,000
- Plant total: 21,300 / 20,000 = 1.065 kg CO2 per unit
- Add plastics, membrane, filters and pump for the full figure

Inputs are illustrative; use your own bills and production records.

## What Senseible does here

Senseible reads the plant's electricity bills (CEA grid factor 0.710 kg CO2 per kWh, CO2 Baseline Database version 21.0) and fuel invoices (IPCC 2006 defaults) into a fingerprinted Scope 1 and 2 record, the plant-level input to a per-unit figure. Bought-in materials go to the supplier evidence trail; product reports are self-declared drafts.

- [Product carbon footprint calculator](https://senseible.earth/calculators/product-carbon-footprint)
- [Air cooler footprint per unit](https://senseible.earth/answers/air-cooler-carbon-footprint-per-unit)
- [Mixer grinder footprint per unit](https://senseible.earth/answers/mixer-grinder-carbon-footprint-per-unit)

Sources: [GHG Protocol Product Standard](https://ghgprotocol.org/standards), [ISO 14067:2018, Carbon footprint of products (iso.org)](https://www.iso.org), [IPCC 2006 Guidelines, Volume 2 Energy (fuel defaults)](https://www.ipcc-nggip.iges.or.jp/public/2006gl/vol2.html), [CEA CO2 Baseline Database, version 21.0](https://cea.nic.in/cdm-co2-baseline-database/?lang=en)

Last reviewed 2026-10-20.