Updated: Jun 30
Here are all answers you need to wisely plan and provide water storage for your home. What water tank size your home needs? or how powerful pump you need to install? You can also use facts and figures explained below as benchmarks to check water usage of your home.
Your daily water need and number of people living in the house are two basic figures to calculate what water tank size or what water pump you need. So first lets see what is benchmark for daily water need of a person. Below diagram shows breakup which sums up to 100 liters per person per day.
A person drinks about 3 liters of water per day (3.5 for men and 2.5 for women). 1 liter extra is added for water used in other drinks such as tea, lassi etc. Cooking use is about 4 liters per day per person. This figure includes washing, soaking and cooking (daal,sabji,roti,rice etc).
Personal hygiene accounts for 20 liters, which includes washing hands, face and body. This figure may vary depending upon personal hygiene habits. We have taken it at minimum must. Sanitation consumes about 40 liters of water per person per day. This includes use of water in flushes, floor cleaning etc. Washing is factored at 32 liters per person per day. Washing includes washing of utensils and clothes.
With daily water needed by a person at 100 liters, now we can calculate what water tank size your home needs by factoring in number of people living in house and adjusting it for other purposes (will explain later), first lets check water tank size calculation below
Calculating per person need of a home is fairly easy, just multiply number of people to daily water need of a person. 2nd column in above table tells us just that. But a home needs more water than that for many reasons which may differ from home to home. Like green companions (plants) in home. Water for potted plants or your garden also need to there. Also you need have some extra water people visiting your home. Also a home need to store water just due to "no power" hours in India. To factor in such reasons, we have adjusted personal water need of a home by a factor 1.5 to arrive at standard water storage needs of an India home.
So to say 300 liters of personal needs becomes 450 (300x1.5) liters when adjusted to other purposes, 3rd column of above table conveys that. 4th column shows nearest water tank size (in liters) available in market and column 5th indicates how many times you may need to run a pump per day to secure water for your home.
It is important to mention here SensaSwitch water level alarms and automation helps you to keep water tank size minimum as they accurately convey and control water pumping needs. Also to ensure circulation of water, it is good to keep water tank storage to minimum possible.
Finally we calculate how powerful pump you need. Pump power needed basically depends upon the height (called head) of water tanks from water pump position. What you basically need to do is add height of your water tank from ground and depth of your water pump below ground. Suppose your home rooftop is 40 feet from ground your water pump is in under-ground water tank of 10 feet depth, you motor head is 50, sum of 40 and 10. With head figure, below tables shows what pump power you need.
Please note water delivered by a pump is subject to many other factors also like, size of delivery pipe, bends in water pipe and even power voltage level at a point of time. The figures indicated in 3rd column indicate general figures to work around. As we have taken water tank size of 500 liters for all rows in tables, the run time for pump will need to be adjusted for water tank size your have or need. Simply said if you have 1000 liter water tank on rooftop, run time become double (2x).
Pump run time and runs per day also help in knowing your need for water level alarm of automation. If your pump time is about 15-20 minutes or less and you need to run pump only once / twice per day, you can choose a water level alarm. In case you can run pump once or twice per day but can not commit to wait till tank fills, you can opt for a overflow auto-stopper control. For people living in fast lane (like pros and business people), fully automatic water pump control is must. Even for homes where water pump needs to be run more then 2-3 times a day, fully automatic water level control means plenty of water with peace of mind. Automatic water level controller can also be used to avoid trouble some air-traps or air-locks in water pipes.