  We characterize the absolute magnitudes and colors of RR Lyrae stars in the
globular cluster M5 in the ugriz filter system of the Dark Energy Camera
(DECam). We provide empirical Period-Luminosity (P-L) relationships in all 5
bands based on 47 RR Lyrae stars of the type ab and 14 stars of the type c. The
P-L relationships were found to be better constrained for the fundamental mode
RR Lyrae stars in the riz passbands, with dispersion of 0.03, 0.02 and 0.02
magnitudes, respectively. The dispersion of the color at minimum light was
found to be small, supporting the use of this parameter as a means to obtain
accurate interstellar extinctions along the line of sight up to the distance of
the RR Lyrae star. We found a trend of color at minimum light with pulsational
period that, if taken into account, brings the dispersion in color at minimum
light to < 0.016 magnitudes for the (r-i), (i-z), and (r-z) colors. These
calibrations will be very useful for using RR Lyrae stars from DECam
observations as both standard candles for distance determinations and color
standards for reddening measurements.
