ashes.

Numbers 19:9
Then a man who is clean is to gather up the ashes of the heifer and store them in a ceremonially clean place outside the camp. They must be kept by the congregation of Israel for preparing the water of purification; this is for purification from sin.

running water shall be put thereto.

Genesis 26:19
Then Isaac's servants dug in the valley and found a well of fresh water there.

Song of Solomon 4:15
You are a garden spring, a well of flowing water streaming down from Lebanon.

John 4:10, 11
Jesus answered, "If you knew the gift of God and who is asking you for a drink, you would have asked Him, and He would have given you living water." . . .

John 7:38
Whoever believes in Me, as the Scripture has said: 'Streams of living water will flow from within him.'"

Revelation 7:17
For the Lamb in the center of the throne will be their shepherd. He will lead them to springs of living water, and God will wipe away every tear from their eyes.'"