Civil Engineering Materials #$6\mathrm{.}22$

In order to evaluate the suitability of nonpotable water available at the job site for mixing concrete, six standard mortar cubes were made using that water and six others using potable water. The cubes were tested for compressive strength after $7$ days of curing and produced the loads to failure $($in pounds$)$ shown in Table.

Based on these results only, would you accept that water for mixing concrete according to ASTM C$94?$

According to ASTM C$94,$ are there other tests to be performed to evaluate the suitability of that water? Discuss briefly.