I'm working on a ruined city for a fantasy adventure and developing charts to help me fill in details for the approximately 400 buildings on the map I drew up. Here's the charts for cisterns and the state of the roof. Most of the roofs in these ruins are flat topped so the rooftops offer more opportunity for action and encounters.
1-25 No rooftop cistern
26-35 Slow leak,in cistern compromising integrity of roof.
36-40 Empty and broken cistern.
41-45 Empty and broken, integrity of roof is compromised.
46-50 Intact but Empty cistern.
51-60 Cistern contains potable water.
61-65 Cistern appears to contain potable water, it isn’t.
66-80 Cistern contains clearly foul water.
81-85 Cistern contains a scummy water, safe if boiled.
86-88 Cistern is old and lined with bronze that includes arsenic, good luck with that.
89-90 Vermin swim in the stew-like broth in this cistern.
91-94 Vermin swim in the stew-like broth in this fragile cistern fit to burst at any moment.
95-97 Empty cistern is a nest for birds/vermin.
98 Empty cistern holds a body.
99 Full cistern of seemingly potable water contains a body.
100 Cistern full of foul water contains a body.
State of roof
1-5 Intact unremarkable roof.
6-10 Leaky roof.
11-14 Water pooling on roof, leaky but nor dangerous (yet).
15-18 Water pooling on roof, roof is dangerous to walk on.
19-22 Roof appears stable but is unsafe.
21-25 Roof appears hazardous but is safe, for now.
26-30 Roof appears hazardous and is dangerous.
31-34 Small hole in roof.
35-38 Small hole in roof with signs of fire damage.
39-42 Small poorly patch hole in roof.
43-46 Small poorly patch hole in roof with signs of fire damage.
47-50 Large hole in roof.
51-55 Large hole in roof with signs of fire damage.
56-59 Large poorly patched hole in roof.
60-64 Large poorly patched hole in roof with signs of fire damage.
65 Well maintained rooftop garden. (hmm someone must be taking care of it)
66-68 Overgrown rooftop garden.
69-71 Overgrown rooftop garden, vermin lurk in cover.
72-75 Overgrown rooftop garden, conceals weak points in danger of collapse.
76-79 Abandoned and barren rooftop garden.
80-82 Abandoned and barren rooftop garden, water pooling here and there.
83-85 Abandoned and barren rooftop garden, water pooling here, roof is dangerous to walk on.
86-90 Half collapsed roof.
91-95 Mostly collapsed roof.
96-100 Completely collapsed roof.