As a result,there is a clear dissimilarity between the provinces regarding the
water quality in the DS (SI5). Average free Cl levels are also (significantly)
more important in NL small systems than in QC systems (Fig. 2a). In
fact, the higher levels of TOC and UV254 in the water to be chlorinated in
NL lead to higher chlorine demand. Higher chlorine demand requires
higher chlorine doses for secondary disinfection purposes allowing
higher free chlorine levels in the DS.