_QUANTITY OF WATER REQUIRED FOR DOMESTIC USE_
Until the last few years it has been a sad commentary on the
intelligence of the average farmer that but few attempts have been made
to supply the farmhouse with running water, adequate to the needs of
domestic use. The men of the farm long ago realized that carrying water
for stock in pails was both laborious and time-consuming, and very few
barnyards have not had running water leading into a trough to supply the
needs of cattle. In many cases this supply has been extended into the
barn, and in some cases into individual stalls, so that the farmer has
long since eliminated the necessity of hauling water for his stock.
Perhaps, because the farmer did not himself carry the water, but rather
his wife, he has until recently not concerned himself with any extension
of the water-supply into the house, and so long as the well in the yard
did not run dry, he felt that his duty had been done. To be sure,
bringing water from the well to the house in mid-winter involves much
exposure and sometimes real suffering; occasionally the farmer has been
moved on this account to have the well located in the woodshed or on
the back stoop, avoiding the long outdoor trip, but increasing the
dangers of pollution to the water. It would be interesting to make a
census of the farm water-supplies in any county for the purpose of
estimating the intelligence of the farm-owners, since one cannot but
feel that such a primitive water-supply argues, in most cases, an
undeveloped or one-sided intelligence on the part of the property owner.
_Modern tendencies._
Happily, such primitive methods of bringing water to the house are being
superseded by satisfactory installations, and one by one, each farmhouse
is being provided with running water in the kitchen sink and with a
bath-room containing all the modern conveniences. One cannot deny that
this costs money, both because of the pipe line necessary to bring the
water to the house and because of the plumbing fixtures required in the
house. Again, a water-supply in the house involves a well-heated house,
since pipes not kept warm will, in the winter, inevitably freeze,
ruining the pipe line and perhaps the ceilings and walls of the house
itself. But if the owner of a house has any money to expend in
improvements, surely no better way of adding to the comfort and health
of his family can be found. An abundant supply of water increases the
self-respect of the whole family and has been known even to change the
temper of an entire household. For another reason, also, it is a good
investment, inasmuch as the quality of the water supplied from a spring
on a hillside is, generally speaking, better than that of a well
surrounded by barnyards and privies.
It has been said that the civilization of a community is measured by
the amount of soap that it consumes, and it is almost the same thing to
say that the refinement of a household is measured by the amount of
water it uses. The poorer a family, the greater struggle it is to keep
up the appearance of cleanliness, and no surer sign of rapid progress on
a downhill road can be found than neglect of those practices which tend
toward personal neatness. As the life of the farmer, then, becomes
easier, as his condition becomes more prosperous, and as his family make
more requirements, so, inevitably, is there in the farmhouse a greater
demand for water in the kitchen, in the laundry, and in the bath-room.
_Quantity of water needed per person._
Just how much water is needed in any house is not easy to predict,
unless, at the same time, it is known, not merely the present habits of
the family, but also their capacity to respond to the refining influence
of unlimited water.
It has been shown by measuring the amount of water used in families of
different social standing in cities of New England that the amount of
water varies directly with the habits and social usages of the family.
For example, in Newton, Massachusetts, where there are a large number of
small houses with the water-supply limited to a single faucet, it was
found that the water used amounted to seven gallons per day for each
person in the house, while in houses supplied with all modern
conveniences, the consumption of water was at the rate of twenty-seven
gallons per day for each person. In Fall River, the conditions were much
the same except that the poorer houses generally had one bath-tub and
one water-closet, the amount of water used being eight and a half
gallons per head per day, while the most expensive house in the city
used twenty-six gallons per head per day. In Boston, the poorest class
apartment houses used water at the rate of seventeen gallons per head
per day, the moderate class apartment houses at the rate of thirty-two
gallons, first-class apartment houses at the rate of forty-six gallons,
and the highest class apartment houses at the rate of fifty-nine gallons
per head per day. The difference in these rates is easily understood by
considering the habits of the individuals who make up the different
classes referred to. In the poorer class of houses, the workers of the
family are gone all day, and are too tired when home to spend much time
in bathing. The children of such households are washed only
occasionally, and the external use of water is generally regarded as an
unnecessary trouble. In those families, on the other hand, where the
necessity for daily toil is not so pressing, where bathing is more
frequent, and where ablutions during the day are more often repeated,
the amount of water used is much larger.
Another factor that affects the measured amount of water used in a
family is the number of plumbing fixtures. At first sight, it would not
seem possible that because there were two wash-basins in a house, an
individual should use more water than if there were only one basin. Nor
would it seem possible that an individual would take more baths with
three bath-rooms available than if only one existed, and yet the number
of fixtures does influence the individual who washes his hands
frequently. With a wash-basin on the same floor, for instance, he washes
often, whereas if it were always necessary to go upstairs for the
purpose, his hands would go unwashed. Also, the more fixtures there
are, the greater is the amount of leakage, since every faucet will, in
the course of time, begin to leak unless the packing is continually
replaced. The amount of leakage is, therefore, in direct proportion to
the number of fixtures.
The amount of water used then, per head per day, varies from seven to
sixty gallons, but only by an intimate knowledge of the habits of the
household can one predict the amount of water likely to be used. Perhaps
as an average in a house having a kitchen sink and a bath-room
containing a wash-basin, bath-tub, and water-closet, a fair estimate of
the water used would be twenty-five gallons per head per day. This
amount must be multiplied by a maximum number of persons to be in the
house at any time, and then this number must be increased by the amount
of water used in the barn and in the yard, if these are to be supplied
from the same source as the house.
_Quantity used in stables._
The amount of water used in the barn is even more than that used in the
house, a variant depending on the habits of the manager. The minimum
quantity needed per day is determined by the number of pailfuls of water
which each head actually drinks multiplied by the number of head. But
besides this there are many other uses to which water may reasonably be
put in connection with stock.
On a dairy farm, there is the water needed to wash cans and bottles and
in some cases to furnish a running stream of cold water for the aerator.
In some stables a large amount of water is used for washing harnesses
and carriages; in others, but a small amount goes for such purposes.
Some farmers have concrete floors in cow stables and pig pens and use a
hose frequently to wash these floors clean. Other stables never see a
stream of water and only see a shovel at infrequent intervals. The
amount of water used outside the house is too uncertain a quantity to
estimate on the average, but its influence and importance must not be
overlooked.
_Maximum rate of water-use._
It should now be noted that the quantity of water already referred to is
the average quantity used through the twenty-four hours and does not
mean the rate at which the water comes from the faucet. For example,
three persons in a house use water, according to the above statement, at
the rate of seventy-five gallons per day, but a whole day has 1440
minutes, and if seventy-five gallons be divided equally among the number
of minutes, it means one gallon in every twenty minutes, or one quart in
five minutes. It is obvious that no water-supply system for a house,
designed to supply water at the average rate for the twenty-four hours
would be satisfactory, since no person would care to wait all day for
the amount. To wait five minutes to draw a quart of water would try the
patience of any one, and while the total amount of water used in the
house will be seventy-five gallons, provision must be made by which it
can be drawn in small amounts at much higher rates. Practically all of
the amount is used in the daylight hours or in twelve hours out of the
twenty-four, so that the rate would be twice the average rate, and with
this correction, two quarts of water could be drawn in five minutes.
But even this is too slow, and if one were to take a quart cup to a
kitchen faucet and note the time necessary to fill the measure with the
water running at a satisfactory rate, he would find that unless the cup
was filled in about ten seconds it would be considered too slow a flow.
Since it is possible for more than one fixture to be in use at the same
time, the pipes ought to be able to deliver the total amount running
from different faucets open at the same time, and if it is considered
possible for three faucets to run at once, as, for instance, the kitchen
faucet, bath-room faucet, and barn faucet, then the supply pipe must be
able to deliver, under our assumption, three quarts in ten seconds, or
at the rate of about six thousand gallons a day. It is necessary,
therefore, to distinguish carefully between the total quantity of water
used per day and the rate at which such water is used.
The first of these requirements governs the size of the reservoir from
which the water comes or the yield of the well or spring, or the
capacity of a pump from a pond to a distributing tank; the other
requirement governs the size of the pipe or faucet or the capacity of a
pump which supplies direct pressure. It should be noted also that with
ordinary fixtures, the rate of delivery and the corresponding sizes of
the fixtures are not affected by the number of persons in the house,
whereas the first requirement, that is, the total quantity of water used
per day, is directly affected by the number of persons.
_Variation in maximum rates of water-use._
The quantity of water used, however, is not uniform throughout the day
or the week. It is commonly known, for instance, that on Monday, or
wash-day, when the well is the only supply, a great deal more water has
to be carried on that day than on any other day in the week, and this
same increased demand for water is made when the water comes in pipes
into the house. Probably about half as much water again is used on
Monday as on other days.
Again, in the hot weather of summer, more water is used for bathing and
laundry purposes than in cold weather. But, on the other hand, there is
a great tendency in cold weather to let the water run in a slow stream
from faucets in order to prevent freezing. This has been found to just
about double the amount of water used. It is only a reasonable
safeguard, therefore, if it has been decided that the family needs are
such as to require twenty-five gallons per head per day, to provide for
double that amount in order to meet the demands of excessive daily
consumption or of the hot and cold weather extremes.
_Fire streams._
If a water-supply is to be installed for any house, the possibility of
providing mains of sufficient size for adequate fire protection should
always be considered, although it may not be found to be a necessary
expenditure. In case of a fire a large amount of water is needed for a
few hours, entirely negligible if it is computed as an average for the
year, but a controlling factor in determining the size of mains or the
amount of storage.
A good-sized fire stream delivers about 150 gallons per minute, and for
a house in flames, four streams are none too many. The rate of delivery,
therefore, for a fire should be at least 600 gallons per minute or a
rate of nearly a million gallons per day, and if it is assumed that the
fire might burn an hour before being extinguished, 36,000 gallons of
water would be used. If a spring or tank is the source of supply, the
storage should be 36,000 gallons, and the pipe line from the tank to the
hydrants must be large enough to freely deliver water at the rate of 600
gallons per minute. If the distance is not over 500 feet, a four-inch
pipe is sufficiently large; but if the distance involved (from the
reservoir or tank to the farthest hydrant) is more than about 500 feet,
four-inch pipe is not large enough. This is because the friction in a
large line of pipe is so great that the water cannot get through in the
desired quantity. A four-inch pipe, discharging 600 gallons a minute,
would need a fall of one foot in every four feet, while a six-inch pipe
would need a fall of only one in thirty. Of course, if the reservoir
from which the water comes is at such an elevation that the greater fall
is obtainable, the smaller pipe may be used. It is more than likely,
though, that the reservoir is about 3000 feet or more away, and the
entire fall available only about thirty feet or one foot in one hundred.
Then an eight-inch pipe would have to be used.
Whether fire-protection piping, therefore, is a wise investment or not,
depends largely on the cost of installation. A four-inch cast-iron pipe
laid will cost about forty cents per running foot, while an inch pipe,
large enough for everything except fires, will cost about ten cents, so
that the excess cost per foot for the sake of fire protection is thirty
cents, for a distance up to 500 feet (when the grade is 1 to 4) or $150.
If the grade is not 1 to 4, then the pipe must be six-inch, and the
excess cost is fifty cents or the cost for 500 feet will be $250. If the
distance is greater than 500 and the fall not great, so that an
eight-inch pipe has to be used, the excess cost is sixty-five cents a
foot, or $650 for a 1000-foot line.
It is sometimes possible to economize by building a large tank
containing about 36,000 gallons and using only a small pipe to fill, but
always keeping the tank full. Such a tank would contain 4800 cubic feet
or would be twenty-two feet square and ten feet deep, or it may be
twenty-five feet in diameter and ten feet deep. This tank would have to
be erected in the air, higher up than the top of the buildings, and
would require heavy supports and a great expenditure. Unless, therefore,
a convenient knoll or sidehill is available on which to build a concrete
tank, the large pipe direct from the water-supply must be provided for
fire protection. Whether it is worth while depends on the cost of
insurance and whether it is considered cheaper to pay high rates for
insurance or to spend the large sum for protection. A third choice is
also open, namely, to carry no insurance and to install no fire hydrants
and to run the inevitable risk of losing the house by fire. Perhaps the
decision is a mark of the type of man whose property is concerned.
_Rain water-supply._
It will often happen that no pond or brook is available for a
water-supply, and if water is obtained, it must come directly from the
rain. Apparently, this is quite feasible, since an ordinary house has
about 1000 square feet area on which rain water might be caught and
carried to a tank. In the eastern part of the United States, the annual
rainfall is, on the average, 3-3/4 vertical inches per month, or the
volume of water from the roof will be 310 cubic feet. This is nearly 80
gallons a day, or enough for three or four people. The rain from the
house and barns might be combined, making perhaps 5000 square feet, and
giving an ample volume of water for the needs of a dozen people.
In discussing the size of tank necessary to hold rain water for a family
supply, it must be remembered that for many weeks at a time no rain
occurs, and that a tank must be large enough to tide over these
intervals of no rainfall. In the temperate zone there is no regularity
in the monthly rates of rainfall. In the eastern part of the United
States, the months of June and September are usually the months of least
precipitation, although the general impression, perhaps, is that July
and August have less rainfall than any other months. The truth is that,
while wells and rivers are low in July and August, the actual rainfall
for those months is not below the normal, and the low flows in the
streams are caused by excessive evaporation and by the demands of
growing crops. Although June and September have usually less rainfall
than other months, in Boston the fall has been as high as 8.01 inches in
June and 11.95 inches in September. Again, in Boston, typifying the
eastern part of the United States, and taken because of the great length
of rainfall statistics available there, the two months of highest
rainfall on the average are March and August, and yet, in each month, in
some particular year, the rainfall has been the lowest for any of the
twelve months in the year.
As shown by statistics, the average rainfall in each month, taking a
period of forty years or so, is practically constant for each month, and
it is only the deviations from the average which would make trouble in a
supply tank depending upon rainfall. Fortunately, statistics also show
that while a month whose average rate of rainfall is three inches may be
as low as three tenths of an inch, it is not often that two months of
minimum rainfall come together, and in looking over the rainfall
statistics the writer finds that for any three consecutive months,
including the minimum, the amount of rainfall is generally two thirds of
the monthly average for that year; and this is stated in this way
because it gives what seems to the writer a basis for determining a fair
and reasonable capacity of a rain-water storage tank. It depends, one
will notice, on the average annual rainfall; that is, on the depth to
which the rainfall would reach in any year if none ran off. This varies
from about ten inches in the southeastern part of the United States to
one hundred inches in the extreme northwest, the average for the eastern
part of the country being about forty-five inches, so that the monthly
average is 3.75 inches.
_Computation for rain-water storage._
With this for a basis, it may be determined how large a storage tank
ought to be, assuming a family of five persons using water at the
average rate of 25 gallons per head per day or 125 gallons each day.
Doubling this amount to take care of emergencies and of the extra water
used in hot weather, let us say that 250 gallons a day must be provided,
or 7500 gallons a month. If we could be sure of starting at the
beginning of any month with the tank full and that exactly thirty days
would be the period of no rainfall, then a tank holding 7500 gallons
would be the proper size. Unfortunately, with any month, as August, in
which the rainfall may be practically zero, the preceding month may also
have been so short of rain that the consumption was equal to or even
more than the rainfall, and the month of August would start with no rain
in the tank.
But if we take a three-month period, those inequalities will be averaged
and the supply will be, so far as one can foresee, ample in amount; that
is, we shall take the supply required in three months, namely, 22,500
gallons, and subtract from it the amount of water furnished in the three
months, which is presumably two thirds of the average rainfall on the
area contributing to the tank. The normal rainfall in three months is
three times 3-3/4 inches, or 11-1/4 vertical inches, and if this falls
on a roof area of, say, 2000 square feet, the total amount of water is
1850 cubic feet or 13,875 gallons, and two thirds of this is 9250. The
tank, then, must hold the difference between the 22,500 gallons and
9250, or 13,250 gallons, whereas a month's supply would be 7500 gallons.
The actual tank, therefore, is made to hold a little less than two
months' supply. Such a tank would be ten feet deep and fourteen feet
square, a good deal larger tank, of course, than one ordinarily finds
with a rain water-supply; but the estimate of the use of water has been
high and a long period of rainfall has been assumed, so that there is
little likelihood of a house with this provision being ever without
water.
_Computation for storage reservoir on a brook._
In determining the quantity of water that may be taken from a small
stream the area of the watershed answers the same purpose as the area of
the roof which delivers water into a tank, the only difference being
that from the roof all the water is always delivered, except a small
proportion that evaporates at the beginning of a rain in summer. From
the surface of a watershed, on the contrary, a large amount, and in
some cases all of a stream, will be absorbed by the ground and by the
vegetation and will never be delivered into the stream which drains an
area. On large streams it is fair to assume that, on the average, only
one half of the rainfall on the area will reach the stream, while with
sandy soils this may be as small as 20 per cent. From December to May
inclusive, when the ground is frozen, when there is no vegetation to
absorb the water, and when evaporation is very light, practically all of
the rainfall reaches the streams. From June to August, on the other
hand, when the soil becomes rapidly parched, when vegetation is most
active, and when evaporation is high, frequently no rainfall reaches the
streams and the ground water sinks lower and lower, so that often
streams themselves dry up. It is necessary, therefore, in providing for
a definite quantity of water to be taken from a reservoir built on a
small stream, to make the reservoir large enough to furnish water from
June to September without being supplied with rain. This does not call
for a very large dam or a very large storage, and three months' supply
will usually be ample.
We have already estimated above that the quantity of water needed for
three months will be 45,000 gallons, or about 6000 cubic feet. If the
reservoir is built in a small gulley or ravine, its width may be
twenty-five feet. If the length of the reservoir or pond formed by the
dam is 240 feet, then the reservoir will furnish 6000 cubic feet for
every foot of depth, and a reservoir of that size holding one foot of
water will tide over a dry season.
Evaporation during these same three months will use up about a foot and
a half in depth over whatever area the reservoir covers, so that two
and a half feet in depth must be provided above the lowest point to
which it is desirable to draw off the water. It would be well to allow a
depth of at least ten feet in order to avoid shallow, stagnant pools,
and if this depth is provided, even more than the two-and-a-half foot
depth mentioned might be withdrawn in extremely dry seasons, though
perhaps at some reduction in the quality of the water.
_Deficiency from well supplies._
A large number of water-supplies in the country, perhaps the largest
number, at present comes from wells, either dug or drilled. It often
happens that after plumbing fixtures have been installed with a pump to
raise the water to the necessary elevated tank, the increased
consumption causes the well to run dry for a number of weeks in the
summer. The question then arises, Shall the well supply be supplemented
or shall an entirely new supply be developed?
There are two methods of supplementing a dug well supply, and it may be
of advantage to point them out. If the sand or gravel in which the water
is carried is fine, it may be that the water will not at times of low
water enter the well as fast as the pump takes it out. Such a well
always has water in it in the morning, but a short pumping exhausts the
supply. One remedy here is to provide a more easy path for the water,
and that can be done by running out pipe drains in different directions.
If there are any evidences that the underground water flows in any
direction, then the drains should preferably run out at right angles to
this direction, to intercept as much water as possible. The drains must
be laid in trenches and be surrounded with gravel, and of course the
method is inapplicable if the well is more than about fifteen feet deep,
because of the depth of trench involved.
[Illustration: FIG. 22.--How a pump works.]
Another remedy is to sink the well deeper, hoping to find a more porous
stratum or to increase the head of water in the well. In one well, the
writer remembers seeing two lengths of twenty-four-inch sewer pipe, that
is, four feet, that had been sunk in the sandy bottom of the well by
operating a posthole digger inside and standing on the top of the pipe
to furnish the necessary weight for sinking.
Still another remedy is to drive pipe down in the bottom of the well,
hoping to find artesian water which will rise into the well from some
lower stratum. This method has been successfully employed in the village
of Homer, New York, where the public supply formerly came from a dug
well twenty feet in diameter. The supply becoming deficient, pipe wells
were driven in the bottom and an excellent supply of water found fifty
feet below the surface, the water rising up in the dug well to within
eight feet of the surface of the ground.
If the well is a driven well and the water in the casing falls so low
that the ordinary suction pump will no longer draw, two remedies may be
applied. A so-called deep-well pump may be used; that is, a pump which
fits inside the piping and can be lowered down to the water level. The
ability to bring up water then depends on the power to work the pump and
on the presence of the water. Figure 22 shows the principle on which
this pump works. At some point, it may be three or four hundred feet
below the surface of the ground, a valve _A_ opening upward is set in
the well so that it is always submerged. Just above this is a second
valve fastened to the lower end of the long pump rod which reaches up to
the engine or windmill which operates the pump. At each up stroke water
is lifted by the closed valve _B_ and sucked through the open valve _A_.
At each down stroke, the water is held by the closed valve _A_ and
forced up through the open valve _B_.
[Illustration: FIG. 23.--Pump installation.]
The other method of developing a greater quantity of water from a deep
well is to use air pressure to force the water either the entire
distance to the tank or to a point where the suction of an ordinary pump
can reach it, as indicated in Fig. 23. In this method an air blower is
needed, and since this means an engine for operation, it is not
generally feasible, but is suited to occasional needs, where an engine
is already installed for other purposes and is therefore available.
The operation is very simple. An air pipe leads from a blower and
delivers compressed air at the end of the air pipe, which must be below
the level of the water in the well. The pressure of the air then causes
the water to rise, the distance depending on the pressure at which the
air is delivered.