▁remaining ▁today ▁from ▁the ▁ 1 3 th ▁century . ▁These ▁res er voir s ▁would ▁be ▁sub ter rane an ▁spaces ▁that ▁were ▁connected ▁to ▁the ▁network ▁of ▁kar iz ▁in ▁the ▁city . ▁A ▁typical ▁resident ial ▁ab ▁an bar ▁would ▁be ▁located ▁in ▁the ▁en closed ▁garden , ▁have ▁the ▁capacity ▁to ▁hold ▁ 5 0 ▁cub ic ▁meters , ▁would ▁be ▁filled ▁once ▁every ▁two ▁weeks , ▁and ▁have ▁its ▁inside ▁surfaces ▁clean ed ▁from ▁sed iments ▁once ▁a ▁year ▁( called ▁lay eh - r ub i ). ▁ ▁So on ▁public ▁ab ▁an bars ▁were ▁constructed ▁throughout ▁cities ▁across ▁Pers ia ▁such ▁as ▁Q az vin , ▁Y az d , ▁N ae en , ▁K ash an , ▁Z av are h , ▁Ray , ▁Sh ira z , ▁Her at , ▁B alk h , ▁and ▁others . ▁At ▁the ▁beginning ▁of ▁the ▁ 2 0 th ▁century , ▁the ▁number ▁of ▁public ▁ab ▁an bars ▁in ▁Q az vin , ▁for ▁example , ▁ ▁was ▁recorded ▁to ▁be ▁ 1 5 1 . ▁Yet ▁Iran ▁still ▁has ▁ 3 0 , 0 0 0 ▁active ▁Q an at ▁systems ▁today . ▁ ▁Account s ▁differ , ▁but ▁the ▁water ▁quality ▁generally ▁seemed ▁to ▁be ▁satisf actory . ▁Water ▁temper atures ▁of ▁K ash an ’ s ▁famous ▁Q an at ▁of ▁Ch ash me h - i ▁So le iman ▁amid st ▁the ▁July ▁heat ▁is ▁typically ▁around ▁ 2 5 ▁degrees ▁Cel si