  The gravitational wave (GW) signals from the Galactic population of
cataclysmic variables (CVs) have yet to be carefully assessed. Here we estimate
these signals and evaluate their significance for LISA. First, we find that at
least three known systems are expected to produce strong enough signals to be
individually resolved within the first four years of LISA's operation. Second,
CVs will contribute significantly to the LISA Galactic binary background,
limiting the mission's sensitivity in the relevant frequency band. Third, we
predict a spike in the unresolved GW background at a frequency corresponding to
the CV minimum orbital period. This excess noise may impact the detection of
other systems near this characteristic frequency. Fourth, we note that the
excess noise spike amplitude and location associated with
$P_{\rm{min}}\sim80~\mathrm{min}$ can be used to measure the CV space density
and period bounce location with complementary and simple GW biases compared to
the biases and selection effects plaguing samples selected from electromagnetic
signals. Our results highlight the need to explicitly include the Galactic CV
population in the LISA mission planning, both as individual GW sources and
generators of background noise, as well as the exciting prospect of
characterising the CV population through their GW emission.
