The age of fission neutrons to indium resonance energy (1.46 eV) was measured in mixtures of zirconium and water. Three different volume ratios of metal to water were investigated. The experimental technique of a finite plane fission source with essentially infinite plane detectors was used (which was equivalent to using an infinite plane source with axial detectors). Thus, the theoretical corrections to the measured results were only 1.5% or less. This is the same technique used previously at this laboratory to measure the age in pure water, and comparisons were made with those data. The results indicate a linear variation of the age as a function of metal-to-water ratio.