A general update: 

• added clarity about where and when you can build houses
• simplified wiring and plumbing connection rules
• added clarity about ferret's point acquisition from house squares
• new rule: a RISK mechanic for the ferret, making survival rolls harder RISK is now accrued when you cross roads, chew wires, or step on poisoned squares
• new rule: if a house is built on the ferret, the ferret dies :(
• balance adjustment: houses get -2 points for diluted water instead of 1
• balance adjustment: fresh water plumbing can only support 5 houses instead of 6
• balance adjustment: pest control dilutes water in that square
• balance adjustment: ferret gets 2 points instead of 1 for forest or rock
• balance adjustment: pee in the pipes only dilutes water for two rounds
• added a round tracker on the map page