this kind of water meter can set a dividing point between 2 different levels of used water volumes, and thus have 3 kinds of water charging price. when the monthly used water volume of the user doesn't exceed the demarcation point, normal price is chcrged; when it exceeds the limit point a, a higher price is collected, and if the monthly used water volume exceeds the limit point b, a much higher price will be charged. thus used water volume of the users is rationally restricted, so it can effectively avoid the happening of water waste. staircase price water meter adopts patent technology of rf card, wireless data transmission and the circuit board is sealed by epoxide resin, which completely is waterproof and damp proof. because of elaborately designed circuit, the water meter consumption current is less than 0. 5μa (under normal working conditions), and the 0. 5μa static working current is only used to keep the inside clock chip working. the water meter can work continuously for more than 8 years without changing battery. water sale control software, which supports the staircase price water meter, is easy to operate and learn. the operating staff only needs to fill in the number of people of each household and the per capita water use volume. computer can automatically calculate the limit volume. the water sale software can check, sum up and print various water sale records and set their right limits, record their operation status, to prevent cheating.