# blackwater

CEFR C2 · Noun

Source: https://englishreference.com/word/blackwater
Updated: 2026-08-15

## Definition

waste water from toilets that contains human waste. It is different from greywater, which comes from sinks and showers.

For teachers: wastewater containing human excreta, typically originating from toilets and urinals. Distinguished from greywater by its higher level of contamination and the requirement for more intensive treatment.

## Examples

- The boat has a special tank to hold blackwater.
- Modern eco-friendly buildings often separate blackwater from greywater to treat and reuse the latter for irrigation.
- Effective management of blackwater is a critical component of urban sanitation, as untreated discharge can lead to the rapid spread of waterborne pathogens and severe environmental degradation.

## Usage notes

- Often used in technical, environmental, or plumbing contexts to distinguish between types of domestic waste.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.