High commodity prices are being blamed for a rise in thefts of copper pipes and hot water cylinders from houses left empty after the Canterbury earthquake.
A woman was jailed on Tuesday for selling 22 stolen water cylinders from abandoned houses.
Police say more than 50 thefts have been recorded since the 7.1 quake.
Commodity prices for copper have hit record highs in recent months.
Plumber Stephen Graham says thieves tear the cylinders out of empty houses, damaging pipes which then flood the properties.
However he says thieves are often disappointed because the cylinders only fetch about $130 when sold to scrap merchants.
Police say they are working with scrap dealers to try to trace stolen cylinders.