Lateral force microscopy (LFM) images on polymeric and inorganic substrates demonstrate how water is transported to and from a substrate by the capillary formed by the LFM tip and sample. Although it is known that water qualitatively affects the atomic force microscopy and LFM measurements, herein we report the condition dependent range of sizes of the water menisci formed in the capillary during such measurements. The effect of water in air can change the force of friction by a factor greater than or equal to 2, with the magnitude of this effect dependent on the chemical nature of the sample and tip dynamics. These results have important implications for any analytical measurement-of friction by LFM in air.