Why won't a vacuum pump operate for a well that is deeper than $10\mathrm{.}3$ m $?$

Atmospheric pressure equals the pressure under $10\mathrm{.}3$ m of water and so can push water no higher.

All pumps leak under the pressure from $10\mathrm{.}3$ m of water.

The maximum suck produced by a pump will only lift water $10\mathrm{.}3$ m $.$

The buoyant force will only lift water $10\mathrm{.}3$ m $.$