Written by Ángel Manuel Rodríguez
What happened to the blood that was poured out at the base of the altar of burnt offerings in the Israelite sanctuary? How was the altar kept clean?
The Bible does not tell us how the blood was disposed of after the sacrificial act was finished. We are informed only that it was to be poured out at the base of the altar (e.g., Lev. 4:7). From the aesthetic and hygienic point of view it would not be elegant or healthy to have that much blood left at the base of the altar. So people often want to know what happened to it.
Sometimes we are able to find pieces of information in the Bible that could be used to throw some light on a particular issue. It is also useful to examine extrabiblical materials in an attempt to answer questions for which the Bible does not provide an explicit answer.
With respect to your specific question, archaeology does not seem to be helpful. A number of ancient pagan altars have been found, but an analysis of their structure does not decisively clarify our question. This is understandable if we keep in mind that in the sacrificial systems of the ancient Near East, the blood of the sacrificial victims did not play any significant role. The sacrifice was primarily offered to the gods as food; the blood itself did not have expiatory force.
There are two pieces of biblical information and some extrabiblical sources that could be helpful to us. Let’s examine them.
The Altar of Elijah (1 Kings 18:30-38). During the encounter with the prophets of Baal on Mount Carmel Elijah repaired the altar of the Lord, which was in ruins. Then he “dug a trench around it large enough to hold two seahs [13 quarts] of seed” (verse 32, NIV). It was filled with the water that was poured on the altar. We have here a trench built around an altar that received the water that ran down around the altar. Some scholars have suggested that Elijah rebuilt the altar on the basis of the altar located in the court of the Israelite sanctuary. If that were the case, the altar would have had a trench around it. The trench would have had the purpose of letting the blood flow away from the altar through a channel to some kind of drainage system. Although that is far from certain, it is obvious that such a system would have been necessary in the case of the Israelite altar in the sanctuary.
The Altar of Ezekiel (Eze. 43:13-17). The prophet was shown in vision a four-tiered altar, with each tier about a cubit smaller than the one below. There was at the base of the altar “a rim of half a cubit and a gutter of a cubit all around” (verse 17, NIV). The reference is most probably to a sump, into which the blood of the sacrifices was drained and that consequently kept the court clean from any blood. There is also the possibility that this sump may have led to a drainage system that would have taken the blood away from the temple area itself. Unfortunately, the text does not provide the details that we would need in order to have a more complete picture of the drainage system.
The Temple of Herod. Although we do not have archaeological evidence that can be used to support the idea that there was a drainage system connected to the altar in the Temple of Herod, we do have some Jewish documents that support that idea. Scholars who have studied those sources comment that according to that tradition the base of the altar had two holes, into which the blood of the sacrifices was poured. The holes led to a channel of running water flowing through the court of the Temple down to the Kidron Valley, outside the city. According to the tradition, this water was sold to gardeners, who used it as fertilizer. In this particular case we have a sewer system used to keep the Temple area clean. Some scholars believe that this tradition is, at least to some extent, historically accurate. If that is the case, we have extrabiblical materials supporting the idea that the Temple had a drainage system used to dispose of the sacrificial blood properly. This was most probably the case in the Old Testament sanctuary and Temple.