What does feedwater mean?
Feedwater is a technical noun denoting the water supplied to a boiler or steam generator for conversion into steam. The term is central to power generation, marine engineering, and industrial process plants, where the quality of feedwater directly determines equipment longevity. Before it enters a boiler, feedwater typically undergoes extensive treatment — filtration, deaeration, softening, and chemical dosing — because dissolved oxygen, minerals, and other impurities can cause scaling, corrosion, and catastrophic tube failure under high heat and pressure. The word most often appears in established pairings such as 'feedwater pump', 'feedwater heater', and 'feedwater treatment', which name the machinery and processes of a plant's water circuit. Though rarely heard outside engineering circles, the term captures a genuinely important idea: that ordinary tap water must be transformed into a rigorously controlled fluid before it can safely drive the turbines on which modern electricity supply depends.
nounWater that is supplied to a boiler or other steam-generating apparatus for conversion into steam, especially water that has been treated to remove impurities. It is a chiefly technical term used in engineering contexts.
- Water supplied to a steam boiler or steam generator, especially after treatment (deaeration, softening, chemical conditioning) to prevent scale and corrosion.
"The plant's efficiency dropped after impurities in the feedwater began to scale the boiler tubes."
"Engineers monitor the temperature of the feedwater entering the economizer."
"Poor feedwater quality caused pitting corrosion inside the locomotive's boiler."
Rarely used in the plural; the word normally functions as an uncountable mass noun. Plural forms appear only when contrasting distinct supplies or qualities of boiler water.
"The two plants drew on very different feedwaters, requiring separate treatment regimes."
Without carefully treated feedwater, even the mightiest steam turbine can be destroyed by something as small as a dissolved mineral — boiler chemistry is a multibillion-dollar battle fought over plain old water.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of feedwater
Feedwater is a straightforward English compound of the native words 'feed' (Old English fēdan, 'to nourish') and 'water' (Old English wæter), formed by analogy with other 'feed' compounds such as feedstock and feed line; it arose with steam technology during the Industrial Revolution as engineers needed a term for the supply side of a boiler. Because both elements are Germanic, its closest relatives are not classical cognates but parallel English compounds like feedback, feeder, and waterproof.
How feedwater is actually used
Feedwater belongs to technical register — it is standard vocabulary in mechanical engineering, power generation, marine engineering, and HVAC, but rare in everyday speech. In British and American usage alike it is normally written as one unhyphenated word, though hyphenated 'feed-water' appears in older texts.
Easily confused with feedwater
Groundwater is water held beneath the earth's surface in soil and rock, whereas feedwater is water deliberately piped into a steam boiler.