Older meters run slower and therefore do not measure all the water going through them, particularly at lower flow rates of ¼ gallon per minute or less. The new water meter will accurately measure all the water you use. Every new meter is tested at the factory to ensure that it registers properly. If you see a high bill, it is usually not because your new meter is reading too high; it is because the old meter was running slow or you may have a small leak.