How long did the flood last?

What follows is one scholar’s way of reading this disagreement — a critical-historical view that often concludes the texts genuinely disagree. It draws on the peer-reviewed sources listed below and stands as one position among the answers above, presented for transparency, not as GEBible’s position.

How critical scholarship weighs this: Widely regarded as a genuine contradiction

This summarizes where critical scholarship tends to land on this tension — a report on the field’s center of gravity, not GEBible’s own ruling.

Within a single chapter Genesis offers two numerical frames for the flood. Genesis 7:17 reports "the flood was forty days upon the earth," while Genesis 7:24 and 8:3 state the waters "prevailed upon the earth an hundred and fifty days" and abated only "after the end of the one hundred and fifty days." Read flatly, these are different durations for the same deluge.

The most disciplined harmonization, pressed by Gleason Archer and John Walton, distinguishes phases: the forty days denote the period of rainfall (Gen 7:12, "the rain was upon the earth forty days and forty nights"), while the 150 days denote the longer span during which the accumulated waters held their crest before receding. On this reading the numbers are not rival totals but sequential stages of one event, and the chapter is internally consistent. This is grammatically possible and, taken verse-by-verse in the received text, even natural; Genesis 7:17 does speak of "the flood" rising and lifting the ark, which could be the rain phase, while 7:24 speaks of the waters "prevailing," which could be the standing-crest phase.

The difficulty is that the phased reading treats as a smooth narrative sequence what the documentary analysis identifies as the interleaving of two complete and independent flood accounts. Since Wellhausen, Genesis 6-9 has been a textbook demonstration of the Documentary Hypothesis, and Joel Baden has more recently made it the centerpiece case for the renewed theory. The two strands can be separated cleanly, and each reads as a coherent story on its own. The Yahwistic (J) account works on a forty-day schema: seven clean pairs and one pair of unclean animals (Gen 7:2), a seven-day warning (7:4), forty days of rain (7:12), and Noah waiting in further seven-day intervals to send out the birds (8:6-12). The Priestly (P) account works on a precise calendrical cycle: one pair of every kind (6:19-20; 7:15-16), the fountains of the deep and windows of heaven (7:11), dated by month and day, with the waters prevailing 150 days (7:24; 8:3) and the chronology keyed to specific dates in Noah's life (7:11; 8:13-14).

Friedman's color-coded reconstruction shows the seams precisely: the forty-day notices cluster in J, the 150-day notices in P. Hermann Gunkel had already argued that the doublets — two counts of animals, two accounts of entering the ark, two durations — betray composite authorship rather than authorial redundancy. The forty-day and 150-day figures are not two measurements of one process taken by a single observer; they are two storytellers' independent clocks, fused by a redactor who preserved both rather than choosing between them. That editorial conservatism is itself evidence: a single author inventing a flood story would not generate two incompatible durations, but a compiler honoring two received traditions would.

The phased harmonization is therefore not impossible, but it is a reading imposed on the final form to rescue a unity the text's compositional history does not support. It also has to ignore the way the two numbers belong to two distinct and otherwise self-consistent systems, each with its own animal count, its own trigger for the flood, and its own theological accent — J's anthropomorphic, sacrifice-oriented Yahweh versus P's transcendent, calendar-ordering Elohim.

Where the critical reading lands: at the surface the numbers can be sequenced, but the dual chronology is the literary fingerprint of two spliced sources, and the harmonization presumes a compositional unity the evidence contradicts.