Reference for Gittin 31:2

לא צריכא דאיכא טופח להטפיח הא נמי תנינא טופח להטפיח חיבור

or clean?<span class="x" onmousemove="('comment',' [I.e., if a mikweh has less than 40 se'ahs, water dripping from another mikweh it cannot make up the deficiency; but v. Tosaf. s.v. [H.] ');">²</span>

Jastrow