What's the adjective for rainwater? Here's the word you're looking for.
Included below are past participle and present participle forms for the
verbs rain and rain out which may be used as adjectives within certain contexts.
“In a burger bar lit by primary colours and over-enthusiastic plastic, in a rainwashed seaside northern town, circled by gulls.”
“An annual climber, every day at least one flower untwists to show the colour of a rainwashed blue sky, and by the evening it curls up again, reverting to a darkening purple.”
“A palace of solid marble, rainwashed, simply looks bedraggled.”