Scientist shares startling warning for daily coffee drinkers: 'Perhaps try making less [of it]'

Pouring coffee down street drains contributes to caffeine pollution in waterways, threatening aquatic ecosystems in the process. 

What's happening?

According to Daily Coffee News, a woman received a $200 fine from Richmond council in London for pouring her coffee down the drain before boarding a bus. 

The council later rescinded the penalty, but the incident raised questions about whether discarded coffee can cause environmental harm. 

The publication noted that around 98 million cups of coffee are consumed daily across the U.K., while 2 billion cups are drunk worldwide. 

Kevin Collins, an environmental scientist and the article's author, explained that though a single cup may seem insignificant, millions of daily portions dumped into drains can create major problems for rivers and waterways by adding to caffeine levels that are already present in sewage systems. 

Collins cited a study that examined 258 rivers across 104 countries and discovered caffeine in over half of the sampled sites — even including locations in Antarctica. 

Why is coffee in our drains concerning?

Most of the U.K. operates a combined sewage system in which a single pipe carries both street rainwater and household wastewater to treatment facilities. Greater amounts of caffeine entering those pipes can mean that more is escaping out to rivers and streams. 

Caffeine is resistant to decomposition in aquatic environments, with scientists classifying it as an emerging contaminant that could affect plants and potentially kill insect larvae. 

Wastewater treatment plants remove anywhere from 60% to 100% of caffeine, per Daily Coffee News, depending on the facility, treatment methods, and other variables. 

Coffee also lowers water pH levels and contains organic compounds that deplete oxygen. Nutrients in coffee promote algal growth, which can trigger oxygen depletion in rivers and lakes — stressing marine plants and animals and potentially reducing their lifespans. 

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What's being done about coffee waste disposal?

As Collins stated, "Street drains are part of our water system. Don't put anything into a drain that you don't want to see ending up in a river, lake, on a beach or in the sea."

You can do your part by keeping your coffee out of street drains and the kitchen sink. Collins noted, "If you are constantly throwing away coffee water, perhaps try making less coffee."

Small amounts of diluted coffee can actually nourish your garden plants, though repeatedly applying grounds to the same patch of soil could cause caffeine buildup.

Only brewing what you plan to drink — and avoiding single-use coffee products — helps reduce waste at the source while keeping Mother Nature happy.

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