  We report the discovery of five new dwarf novae from the Hamburg Quasar
Survey (HQS), and discuss the properties of the sample of dwarf novae in the
HQS. The orbital periods of the new dwarf novae are ~105.1 min or ~109.9 min,
114.3+-2.7 min, 92.66+-0.17 min, 272.317+-0.001 min, 258.02+-0.56 min for
HS0417+7445, HS1016+3412, HS1340+1524, HS1857+7127, and HS2214+2845,
respectively. HS1857+7127 is found to be partially eclipsing. In HS2214+2845
the secondary star of spectral type M3+-1 is clearly detected, and we estimate
the distance to the system to be d=390+-40 pc. We recorded one superoutburst of
the SU UMa system HS0417+7445. HS1016+3412 and HS1340+1524 have rare outbursts,
and their subtype is yet undetermined. HS1857+7127 frequently varies in
brightness and may be a Z Cam-type dwarf nova. HS2214+2845 is a U Gem-type
dwarf nova with a most likely cycle length of 71 d. To date, 14 new dwarf novae
have been identified in the HQS. The ratio of short-period (<3 h) to
long-period (>3 h) systems of this sample is 1.3, much smaller compared to the
ratio of 2.7 found for all known dwarf novae. The HQS dwarf novae display
typically infrequent or low-amplitude outburst activity, underlining the
strength of spectroscopic selection in identifying new CVs independently of
their variability. The spectroscopic properties of short-period CVs in the HQS
suggest that most of them are still evolving towards the minimum period. Their
total number agrees with the predictions of population models within an order
of magnitude. However, the bulk of all CVs is predicted to have evolved past
the minimum period, and those systems remain unidentified. Those post-bounce
systems may have markedly weaker Hbeta emission lines compared to the average
known short-period CVs, and probably undergo no or extremely rare outbursts.
