Leech and leach are two words I don’t run across very often as verbs, but when I do … well, let’s just say that sometimes, even an editor needs a little help.
Thankfully, ThoughtCo has an article on how to use these two words:
“The verb leach means to empty, drain, or remove.
“The noun leech refers to a bloodsucking worm or to a person who preys on or clings to another. As a verb, leech means to bleed with leeches or to act as a parasite.”