How to read a water meter.

Meters for measuring water for domestic use are usually graduated in cubic feet - sometimes in gallons. One cubic foot 10,000 is taken commercially as equal to 71/2 gallons. Hence, to reduce a meter reading in cubic feet to gallons, the number of cubic feet should be multiplied by 71/2.

Fig. 45. - Ordinary form of water-meter dial. Reading 11,867 cubic feet.

The ordinary form of dial is shown in Fig. 45. A special form of register which is more convenient to read, is known as a straight-line register and gives cubic feet or gallons directly.

In Fig. 45 the unit is cubic feet and is plainly marked on the dial. If the unit were gallons, the method of reading would be the same. The hands revolve around circles, each divided into ten numbered divisions. The number on the outside of each circle indicates the number of cubic feet for one complete revolution of the hand. The divisions of the circles are numbered alternately in the counter clockwise and clockwise direction. Thus, the first dial (at the bottom) is marked 10 and one division measures 1 cubic foot, the second 100 and one division measures 10 cubic feet, the next is marked 1000 and one division measures 100 cubic feet, and similarly for the remainder. The small dial at the left measuring 1 cubic foot for a complete revolution is disregarded in reading the meter, being used for test purposes. One division of a circle is equal to a complete revolution of the hand on the next lower circle. When a hand is between two figures, the lesser is to be taken. If a hand is very near a figure, whether that figure or the next lower is to be taken can be determined by observing the hand in the next lower circle. Unless the hand on this circle has reached or just passed 0, the lesser figure is to be taken. The best method of reading is from low to high, that is, from right to left. For example, reading the dial shown in Fig. 45 and setting down the figures successively from right to left, there are 7 for units' place, 6 for tens' place, 8 for hundreds' place, and 1 for thousands' place and for ten-thousands' place, or 11,867 cubic feet.

The circles on different makes of dials may be differently located on the dial, but the method of reading is the same as given.

In meters larger than those ordinarily used for household measurement, the lowest graduated circle, the one marked 10, corresponding to units' place in the reading, is sometimes omitted, the lowest circle being then the one marked 100. In this case the meter is read exactly as described above, and a zero added in the units' place.

The dial after reading cannot be set back to zero. The record is continuous. The amount of water which has passed through the meter in a given time is, therefore, obtained by subtracting the first reading from the last. For example, if the meter were read the 30th day of June and again the 30th day of July, the June reading is to be subtracted from that taken in July.

Using the water meter as a measuring appliance.

The amount of water required for a particular use - for example, in watering a lawn - may be determined by first turning off all other outlets and allowing the hose to run, reading the meter at the beginning and end of the period and subtracting the first reading from the second.

Since the meter can only register when water is passing through, should the hands move when all outlets are closed, water is being wasted through some leak. This can be most easily detected by observing the circle marked "one foot," referred to above as being provided for purposes of test.