What does the cryptic crossword clue "Small wave tapped in source of water (9)" mean?

The wordplay uses an anagram. anagram of TAPPED (synonym="TAPPED") + IN (synonym="IN") + S (synonym="small") = STANDPIPE The answer is STANDPIPE.

Small wave tapped in source of water (9)

Guardian Cryptic #29273 | 10 Across | 2024-01-08 flower