Beyond the Quality of the Water in Your Cup: Coffee and Water Resources at Origin


“When water is diverted from streams and rivers, it is no longer available for use by small communities that may already have limited alternatives. Without sufficient water in the stream, aquatic organisms can be wiped out.”


By Adam Kline, Coffee Importer, Atlantic Specialty Coffee Inc.; Andrew Stubblefield, Associate Professor, Humboldt State University; Paul Hicks, Water Resources Coordinator, Catholic Relief Services; Michael Sheridan, Borderlands Coffee Project Director, Catholic Relief Services

Beginning on January 1, 2013, 7,000 families in the city of Matagalpa, Nicaragua had no potable water for two weeks while the municipal water authority cleaned the pipelines. Why? Because their water had been severely polluted by wastewater from coffee mills upstream from the city (El Nuevo Diario 2013).

This case is not an isolated one in Central America. Coffee is a primary source of stream water degradation in coffee growing areas, particularly during the peak harvest season (typically December through February), threatening both the environment and human health. As the global demand for coffee continues to rise, and the specialty coffee industry booms, the industry has a leadership role to play in setting standards and creating incentives for their partners at origin to protect water resources.

This article begins by describing the basic concepts of a watershed, then explains the impact of both (a) coffee production and (b) coffee processing (milling) on water resources, and concludes with suggestions on ways for the U.S. specialty coffee community to protect water resources in the coffeelands.

Coffee and Watershed Function

In Central America, coffee is often grown in high elevation watersheds, at the headwaters of streams and rivers, making coffeelands the sources of water for downstream communities. Both production and processing activities potentially degrade water quality.

A watershed is the entire land surface that catches rainwater and funnels it into a specific river or lake. In simple terms, a good functioning watershed is one where streams run throughout most of the year, there is good water storage (groundwater recharge), and flooding is minimal. In contrast, a poorly functioning watershed has frequent flash floods, with landslides and high rates of soil erosion, and distinct dry seasons when streams do not flow (Vaast et al., 2005)

Generally, in the tropics, the more vegetation there is in a watershed, the better it functions (see Siles et. al, 2010 and Chará-Serna, 2012). So, a dense cloud forest functions very well, while a sparsely vegetated hillside (such as a corn field) functions relatively poorly. Why is this? Basically, rain is a powerful and potentially destructive force; when rain-drops hit bare soil, they forcefully break apart soil particles, washing them downhill and eventually into streams and rivers. (One fascinating study uses the terms “ballistic” and “bulldozers” in reference to the impacts of water drops on soil – see Furbish 2007). The more exposed soils are to rain, the quicker water runs-off, carrying soil alone, causing flash-floods and landslides. The impact of rain on soil breaks down soil particles so fine that they crust or cement on the surface, impeding water infiltration. In contrast, in a dense, multi-canopy forest, the branches and leaves break the force of rain, absorb it, and allow it to fall onto the soil more gently. From there, tree trunks, root structures, and “litter” (organic matter in soils) also slow down the movement of water over the ground, enabling it to better infiltrate into the soil and eventually seep into the groundwater.

So, in terms of watershed functions, on one extreme we have a dense cloud forest, and on the other we have a hillside planted with corn. Somewhere between those two extremes is a coffee farm. The more a coffee farm mimics a dense, multi-story canopy forest, the better it functions as a watershed (Soares et al, 2011). And the sparser the vegetation on a coffee farm, the worse it functions. Land use is constantly in flux, and most land currently planted with coffee was probably covered in forests, crops, or pastures within the recent past. So a key factor for assessing the impact of coffee on water resources is to know what coffee has replaced. If coffee replaces cloud forest, watershed functions will probably degrade, while if coffee replaces annual crops or pastures, watershed functions will probably improve (Goméz-Delgado 2011).

Coffee certification standards (Rainforest Alliance, Starbucks C.A.F.E., UTZ, and others) all emphasize good coffee agroforestry practices to protect water resources (and to improve biodiversity), including planting vegetative buffers in riparian areas, building foot bridges over streams, and protecting land highly vulnerable to landslides.


Impacts of Coffee Production on Watersheds

The two key major impacts of coffee production on water resources are (a) soil erosion and (b) runoff of agrochemicals (i.e., fertilizers and pesticides) into streams and rivers. These two indicators are affected by the way coffee farmers manage their land and their crop.

Soil Erosion

As described above, soil erosion is generally correlated to vegetative cover (or land use) within a watershed: the more vegetation covering soils, the less erosion. But why is soil erosion a problem? First, the loss of topsoil reduces soil fertility and the overall productivity on farms. Second, soil erosion from hillsides carries sediment into streams and rivers. While sedimentation is a natural, continuous process in all streams, when land-use changes rapidly and negatively (such as when forests are converted to crops, or pastures are burned), the rate of erosion increases rapidly, loading streams with more sediment than they can naturally handle, which leads to all sorts of problems: flooding, loss of fish habitat, the rapid siltation of hydro-electric dams, etc.

Roads are an overlooked problem in coffee growing areas. Dirt roads are scraped and scratched into the landscape to improve access to coffee farms each year. Poorly built roads are often the single biggest contributor to erosion and landslides in coffee watersheds (Verbist, et al. 2005), frequently requiring repair at the end of each rainy season. Few coffee standards currently address the problem of roads.


Conventional (meaning non-organic) coffee production relies on the application of agrochemicals for fertilization and to control pests. These agrochemicals often pollute and contaminate streams and groundwater in the coffeelands (Staver et. al 2001).

Fertilizers and Eutrophication

Nitrogen is a key nutrient for plants, and the most common and abundant fertilizer applied to crops, including coffee. It is highly effective, but also often used improperly. And nitrogen-based fertilizer doesn’t just make crops grow, it makes everything grow, including algae (otherwise known as pond scum) in bodies of waters (streams, rivers, lakes). When excessive amounts of nitrogen (and phosphorous) accumulate in bodies of water, algae “blooms”, a process called eutrophication (Zheng and Paul). The algae releases bad odors and tastes into the water making it unfit for human consumption. Nitrogen can also encourage the growth of blue-green algae that produce toxic substances, turning a pond or the bed of a river green, literally overnight. While algae is growing, it can supersaturate the water with oxygen, causing acid to fluctuate wildly. When the algae dies and rots, it removes (or “blinds”) all the oxygen from the water in the process of decomposition. The deoxygenated water causes ammonias to form, as ammonia is an oxygen-free compound of nitrogen. The resulting condition results in the death of fish and most of the aquatic organisms found in rivers and lakes. Furthermore, groundwater beneath coffeelands can become elevated in nitrate from excess fertilization, which is a threat to human health. (Reynolds-Vargas and Richter 1995).


The use of pesticides in coffee crops may contaminate surface water directly from aerial spraying drift, from the erosion of contaminated soil, superficial drainage from rainwater runoff and from cleaning pesticide containers directly in water bodies. Contaminated surface water can harm aquatic life, as well as human health, if used in the public water supply (Soares 2013). There are a number of pesticides commonly used for coffee production (see Craves 2012).

For example, Endosulfan, which is used to control coffee berry borer, is toxic, causes hormone disruption in humans and bio-accumulates in living organisms (Castillo et al 2011). A recent study in Brazil found twenty-four different pesticides in river water from coffee growing regions (Soares 2013). And an unpublished study carried out by the Global Water Initiative in 2012 in fifteen coffee-dominated watersheds in Nicaragua showed high levels of several toxic pesticides in streams that are used for water supply, including Parathion-ethyl,  Azinfos-methyl, and Malathion. (Note that researchers have not yet determined if the source of these pesticides were coffee farms). And we expect high levels of agrochemical in streams in Central America this rainy season (starting in May) after many farmers reacted to the coffee-rust epidemic with excessive use of a range of pesticides and fertilizers. Many of these pesticides are banned in the U.S. and other countries, but continue to be used, legally or illegally, in coffee production.


Coffee Processing: Wasting Water and Wastewater in Mills

The impact of coffee milling on water resources is determined by two factors: the amount of water used during the milling process, and whether and how coffee wastewater is treated after the milling process.

Wasting Water in Mills

Conventional coffee processing demands huge amounts of water, usually drawn directly from highland streams. Traditional, water-intensive mills use water to sort and transport coffee cherry to and through a depulper, a machine that separates the fruit from the bean inside, which is still covered in mucilage.  The coffee is fermented and then washed in order to fully remove the mucilage from the bean. Based on our experience with cooperatives in Central America, it can take 35-60 liters to process a single pound of dry parchment in a traditional wet mill. This translates to millions of gallons of water over the course of a season for even a small mill.  When water is diverted from streams and rivers, it is no longer available for use by small communities that may already have limited alternatives. Without sufficient water in the stream, aquatic organisms can be wiped out. However, a mill using mechanical demucilagers allows farmers to skip the fermentation and washing processes altogether and require less than 11 liters of water per pound of dry parchment—the Holy Grail for water use is to get to a 1:1 ratio (see Von Enden 2012, Guerrero 2012, and Sanchez 2013).

Mill Wastewater

Coffee milling is completely an organic process, involving only coffee cherries and water. No other inputs are needed. So why should coffee milling contaminate water?  Because the wastewater created by washing the mucilage from coffee cherries contains a long list of substances: carbohydrates, proteins, fibers, fat, caffeine, polyphenols, and pectins, nitrates, ammonium, tannic acids, high levels of organic matter and very low dissolved oxygen levels.  This wastewater is one of the leading contaminants of local water sources in coffee-growing communities. (Kebele 2010).  The mucilage is so loaded with sugars and pectin that the viscous wastewater is referred to in Spanish as “aguas mieles,” or “honey waters.”  Naturally-occurring bacteria in water break down the sugars and pectins in the wastewater, but this decomposition process consumes oxygen. The higher the sugar and pectin load in the wastewater, the more bacterial action takes place and the more oxygen is consumed. (This is referred to as biological oxygen demand, or BOD. When BOD is high, this leads to low “dissolved oxygen” in water, or DO.  Just as with the addition of excess nitrogen described earlier in this article, water can be so depleted of oxygen (low DO) that it cannot support organisms, effectively killing a stream or other water board. Foul odors and tastes are released, making the water unsuitable for use by human communities downstream, requiring significant investments to treat the water.

This release of untreated wastewater can be observed throughout the coffeelands.  This is even true on farms that are certified by one or more of the leading sustainable coffee certifiers. However, there are proven technologies for coffee processing that avoid streamwater contamination (see Von Enden 2012, Guerrero 2012, and Sanchez 2013).


Recommendations for the Coffee Industry

Below are eight ideas for how SCAA members can contribute to improved water security through actions within the coffee chain and beyond.

Measure. Track the amount of water used in milling in your supply chain, and the quality of river water downstream from the mills that process your coffee.  Start with just one or two growers or farmer organizations per supply chain. Report the results of your measurement efforts to SCAA through its START database or other channels.  Benchmark your performance against best practices in the industry.

Reforest. In areas where coffee is grown with little or no shade, increased shade cover and biodiversity can protect water sources, improve the rate of recharge of underground aquifers and reduce the sedimentation of streams and run-off of agrochemicals that can contaminate surface water. To reduce erosion, a key place to focus is riparian zones within coffee farms.

Focus on protecting drinking water supplies. Most certification standards refer to “water resources” or “water bodies” in general terms. That’s a great principle and target, but since it is difficult to protect all resources, we believe specific standards should be created to protect water sources (surface and groundwater) that are used for drinking water supplies. Protection efforts should include the actual source as well as recharge areas for these drinking water sources.

Reduce. Work with mills in your supply chain to find ways to reduce water use in the wet-milling process without compromising coffee quality.  Explore new, water-efficient technologies. Mills with mechanical demucilagers remove more than 98 percent of all mucilage, thereby omitting the need for fermentation and washing, significantly reducing the demand for water.

Reuse. If the mills in your supply chain are using traditional water intensive milling processes, work with them to reuse pulping water for the washing process.

Recycle. Regardless of the technologies in use in your supply chain, wet-milling will invariably generate some waste products.  Whether through direct visits or certifiers, verify the wastewater management practices of farms and mills in your supply chain.  Coffee pulp can be filtered from the wastewater and composted for fertilizer. Coffee wastewater can be treated with lye and probiotics to make it acceptable for release into local waterways. Some innovative systems in use in Central America capture methane gas generated during the treatment of coffee wastewater for use as cooking fuel.

Create incentives. Make sustainable water resource management a part of your conversations with other actors in your supply chain.  Work with your supply chain partners to set goals for adoption or improvement of water-friendly farming practices, water-efficient wet-milling and effective wastewater treatment. Give them real incentives to improve.  It can be expensive to upgrade mills or set aside land on coffee farms as conservation areas or buffers. While millers and farmers may eventually be rewarded for good practices with premiums paid on certified products, the challenge is getting the upfront capital to make the investments. Explore strategies for making finance available for farmers, such as the experiences with Root Capital. When you do improve, report that to SCAA through START—take credit!

Policy: Provide advice to local actors on policies and standards. As governments in Central America strengthen and enforce policies around coffee and water, in some cases, the laws are written unreasonably without clear understanding of the coffee industry. Coffee growers and millers want to advocate for regulations that are appropriate and applicable. The specialty coffee industry, through SCAA, could assist their partners at origin by recommending policies, regulations and ordinances, drawing from the best existing standards from around the globe.


A refrain for watershed practitioners is “we all live downstream”. This is true for people living at origin, downstream of coffee farms and mills. But it is also true for the coffee industry, and ultimately the consumers of coffee; damage done to water resources affects the coffee supply chain, and pesticides used in coffee does make it into brewed coffee. So the next time you are sipping a flavorful cup from Central America, think beyond the quality of the water used to brew your coffee. As you sip, picture in your mind where it came from. Think about how you can help to protect the watersheds and the drinking water of the people who grow your coffee, and ensure that this wonderful fruit is always a healthy beverage.

Bruijnzeel, L.A. Hydrological functions of tropical forests: not seeing the soil for the trees? Agriculture, Ecosystems and Environment 104 (2004) 185–228

Further Reading

Bruijnzeel, L.A. Hydrological functions of tropical forests: not seeing the soil for the trees? Agriculture, Ecosystems and Environment 104 (2004) 185–228

Castillo, J.M., J. Casas, E. Romero. 2011. Isolation of an endosulfan-degrading bacterium from a coffee farm soil: Persistence and inhibitory effect on its biological functions. Science of the Total Environment Vol. 412-413,  20–27

Chará-Serna, Ana Marcela. Impacts of agricultural land use on stream ecosystems of the coffee-growing region of Columbia. A thesis submitted for Master of Science, University of Michigan. August 2012. 

Craves, Julie. Blog: Coffee and Conservation:

El Nuevo Diario (Nicaraguan daily newspaper). More than 7000 households without wáter. January 5, 2013.

Furbish, D., et al.,  Rain splash of dry sand revealed by high-speed imaging and sticky paper splash targets. Journal of Geophysical Research: Earth Surface Volume 112, Issue F1, March 2007

Goméz-Delgado, F., et al., Modelling hydrological behaviour of coffee in agroforestry basin in Costa Rica, Hydrol. Earth Syst. Sci., 15, 369G392, 2011.

Guerrero, Juan.  Estudio de Diagnóstico y Diseño de Beneficios Húmedos de Café, IICA Nicaragua. 2011

Kebele, et al., “Environmental impact of coffee processing effluent on the ecological integrity of rivers found in Gomma Woreda of Jimma Zone, Ethiopia”. Pub. Ecohydrology and Hydrobiology, Vol. 10 No. 2-4, 259-270. 2010 

Pimental, David, et. al., Environmental and Economic Costs of Soil Erosion and Conservation Benefits. Science, New Series, Vol. 267, No 5201 (Feb, 1995), 1117-1123. 

Reynolds-Vargas, J., D. D. Richter. 1995. Nitrate in groundwaters of the central valley, Costa Rica. Environment International, Vol. 21, No. 1. 71-79

Sanchez, Leonardo. Aceres Consultants: website on innovative processing technologies:

Siles, P.: Hydrological processes (water use and balance) in a coffee (Coffea arabica L.) monoculture and a coffee plantation shaded by Inga densiflora in Costa Rica, PhD Thesis, Universit´e Henri Poincar´e, Nancy-I, Nancy, France, 153 pp., 2007

Soares, A. F. S.; Leão, M. M. D.; Faria, V. H. F.; Costa, M. C. M.; Moura, A. C. M.; Ramos, V. D. V.; Vianna Neto, M. R.; Costa, E. P. Occurrence of pesticides from coffee crops in surface water. Ambi-Agua, Taubaté, v. 8, n. 1, p. 62-72, 2013. (

Staver, C. et al., Designing pest-suppressive multistrata perennial crop systems: shade-grown coffee in Central America. Agroforestry Systems 10-2001, Volume 53, Issue 2, pp 151-170

Verbist, Bruno, et. al., Factors driving land use change: Effects on watershed functions in a coffee agroforestry system in Lampung, Sumatra. Agricultural Systems 85 (2005) 254–270

Von Enden, Jan. Treatment of wastewater from Arabica coffee processing,

Zheng, Lei., Paul, Michael, Effects of Eutrophication on Stream Ecosystems, Tetra Tech, Inc. 


kline Adam C. Kline is a green coffee trader at Atlantic Specialty Coffee  in San Francisco, California. He has 12 years experience as a green coffee importer and was a barista prior. Adam earned a degree in Latin America Science from UC San Diego & speaks fluent Spanish.  He is the Chair of the SCAA Sustainability Council.

stubble Dr. Stubblefield is Associate Professor of Hydrology and Watershed Management in the Department of Forestry and Wildland Resources, Humboldt State University. He received a M.S. in Forest Management at the University of Michigan and a Ph.D. in Hydrologic Sciences at U.C. Davis. Dr. Stubblefield teaches courses in wildland water quality, watershed management, hydrology and climate change. His research focuses on impacts of land management on water quality in wildland settings.

hicks Paul Hicks is the Water Resources Coordinator for Catholic Relief Services covering Latin America and the Caribbean. Mr. Hicks has worked oversees for over fifteen years in water resources management and agricultural development. His professional focus combines local management and administration of water supply systems with the protection of water sources. He has led the Global Water Initiative in Central America since 2009. Mr. Hicks has a M.S. from the University of California, Davis in International Agricultural Development.

sheridan Michael Sheridan, Borderlands Coffee Project Director, Catholic Relief Services: Michael has worked on coffee for Catholic Relief Services since 2004. From 2004-2007 he worked to increase the consumption of Fair Trade and sustainable coffees in the United States as director of the CRS Fair Trade Coffee Project. Since 2007, he has worked with smallholder farmers in the coffeelands throughout the Americas. Michael currently directs the Borderlands Coffee Project in Colombia and Ecuador and advises other CRS coffee projects in Latin America and the Caribbean. He is based in Quito and publishes perspectives from the intersection of coffee and international development for the CRS Coffeelands Blog at