There are a few factors to consider when choosing the best size of Berkey water filter system for your needs:

1. How many gallons of water do you consume per day? This is an important question to ask when choosing a Berkey filter system.According to research conducted by the USDA, the average person (weighing 154 pounds) should consume about 1/2 gallon of water per person per day, which is why you commonly hear about people needing to drink eight 8-ounce glasses of water per day (that works out to 64 ounces, which is exactly 1/2 gallon). The 1/2 gallon-per-person-per-day rule is the water you need just for drinking during normal activity periods. You should consume more during hot weather or if you are very active or elderly.

Most of our customers find that once they start using their system, they also like to use the filtered water for cooking. Cooking with water from your Berkey water filter basically doubles your use, to 1 gallon per person per day. After many years of customer feedback, we have found that this is the number that is most accurate for most of our customers: 1 gallon of water per person per day.

2. What is the holding capacity of the Berkey filter system? The bigger the holding capacity of the Berkey water filter system, the more reserve use you will have for peak consumption needs. For example, imagine if you had a Travel Berkey (which holds 1.5 gallons) and while you were cooking dinner on a hot day, your children came in the house after being outside with their friends. Together, the children drank six 8-ounce glasses of water (0.4 gallons). You still need to make iced tea (1 gallon), and you need water to boil pasta (1 gallon). To accomplish all of that, you’ll need a total of 2.4 gallons of water. Your Travel Berkey only holds 1.5 gallons. You want to make sure the holding capacity of the filter system you choose is big enough for your peak water consumption needs.

Shop the Berkey Water Filter Systems

3. What is the flow rate of the different Berkey water filter systems? The more filters your Berkey water system has, the faster your unit will produce water and the faster it will recover from peak or sustained water usage. The bigger systems are taller and therefore generate more water pressure, also increasing the flow rate. The numbers shown on the Berkey water filter comparison chart below are for when the unit is completely full. The flow rate will decrease as the level of water in the upper chamber falls.

4. What size Berkey system would be best for my needs?After years of customer feedback and field testing, we found that if you take the flow rate of the system and multiply that by the holding capacity, this number is a good indicator of the maximum number of people that each system would support under normal conditions. If you feel that your water needs are greater than normal or if you plan on using the Berkey water filter for emergencies or anything other than drinking and cooking, we suggest that you purchase a bigger system than indicated on the Berkey water filter comparison chart below. All units produce the same quality of water. In determining which Berkey water system to purchase, keep in mind that the bigger systems produce more water and the smaller systems are more portable.

We make it easy for our customers to shop online. When you’re ready to purchase one of our water filter systems, you can browse and buy right from our website. If you have a question about any of our filters or systems, simply contact us using our toll-free customer service number.

Factors to Consider

Daily Water Requirements

Whereas a quart of water or other fluid daily will sustain life, it is recommended that we drink one-half to one gallon of water per day.  If preparing for emergency, one additional gallon provides added comfort and accommodates increased fluid needs at higher altitudes, for warm climates or special need individuals. An additional one-half to 1 gallon per day is recommended for bathing and hygiene, and to wash dishes.  Please make a determination as to the number of people within the group and whether or not the system will be used for every day use or emergency use.  For our calculations,  we used the highest recommended amount of two gallons required per day.  After determining how much per day per person and how many people in your group refer to the chart above to select the correct size Berkey filter for your needs.

If your water requirements are more than two gallons per person per day or if you plan on using the water filter for anything other than drinking, cooking and hygiene, we recommend that you purchase the next larger size system indicated on the chart above.

 Peak Water Demand

You need to factor in your peak water demand as well.  For instance, you are cooking a meal using your filtered water for coffee, tea, spaghetti etc and then your family arrives using water for drinking.  You do not want your peak water demand to exceed the Holding Capacity of your selected unit.  So you want to make sure the Holding Capacity of the filter system you select is large enough to cover your peak water consumption needs.

System Capacity and Flow Rate

When determining the best size for your situation, consider that the larger the system’s capacity, the less frequently it will need to be refilled.  All filters are configured with two Black Berkey® Purification elements however; the Berkey Light and the four larger stainless steel systems are expandable as to the number of elements installed which means as you add more sets of elements, the higher the Flow Rate and the shorter the Cycle Time is to re-fill the system.

By selecting the largest capacity required for your future needs, you will insure expandability later on.  If you determine that you have increased water needs, an investment in another filter will not be necessary; you can simply order additional sets of filter elements to expand your current system.

Selecting for a Larger Group

There are two Berkey® systems that will accommodate large groups, they are:

The Imperial Berkey® system, when configured with the maximum number of six Black Berkey® purification elements, can purify ~ 400 gallons per day (16.5 gallons per hour). This is enough to provide for up to 200 people on a sustained basis at 2 gallons per day and up to 800 people for short-term emergency needs at 1/2 gallon per day.

The Crown Berkey® system, when configured with the maximum number of eight Black Berkey® purification elements, can purify ~ 625 gallons per day (26 gallons per hour). This is enough to provide for up to 312 people on a sustained basis at 2 gallons per day and up to 1,250 people for short-term emergency needs at 1/2 gallon per day.

If you are selecting a Berkey for a larger group, we advise you to consider purchasing several Sport Berkey® purification bottles as well.  These compact individual purification systems were developed for use in third world countries and are handy when situations requires you be away from the location of your larger purification system.