do water have a constant resistance ?or it is allways variable? when i mesured the resistance of water in my water tank, at first it showed a very large resistance above 2MΩ,after when i bought the tips of multimeter inside the water close togather and took it away to earlyer position,the resistance is rapedly keeps on decreasing. the value reached 10Ω,5Ω,3Ω,.... even it reached 0 Ω,and after it started to go to negative value. so i confused a lot.what is the resistance of water? in fact i need it to design a water level circuit.