Step 1: Determine Your Capacity Requirement
Brita recommends 8-10 cups of water per person per day as the minimum filtered water target. A 2-person household needs 16-20 cups daily -- the Ultramax 18-cup (UBB18) covers this with one daily refill. A 4-person household needs 32-40 cups daily -- the Ultramax 27-cup (UBB27) provides this with one to two daily refills. The Stream 10-cup pitcher suits a single person or couple who prefers a smaller footprint on the counter. The Brita Hub suits households who want unlimited on-tap filtered water without any reservoir management.
Step 2: Assess Lead-Reduction Need
If your home was built before 1986, lead solder was legal in plumbing and may be present in your pipes or fittings. For lead-concern households, the Brita Longlast filter (OB06) used in the Ultramax 27-cup is certified under NSF 53 for lead reduction. The Standard filter (OB03) and Stream filter (RF-100) are NSF 42 only (chlorine, taste, odor) and do not address lead. The Brita Hub BBSF filter is also NSF 53 certified. If lead is a concern, choose the 27-cup Ultramax with Longlast filter or the Hub system.
Step 3: Evaluate Filter Cost Over Time
Standard filter (OB03): $7-9 each, rated 40 gallons, replaced every 2 months per person = $42-54 per person annually. Longlast filter (OB06): $16-18 each, rated 120 gallons, replaced every 6 months per person = $32-36 per person annually. The Longlast filter costs more per cartridge but less per year and requires fewer replacements -- a clear economic winner for households of 3 or more. The Stream filter (RF-100) is rated 40 gallons at $7-9, same cost per gallon as the Standard filter.
Step 4: Measure Counter Space
The Ultramax 27-cup footprint is 11.1 inches wide by 5.3 inches deep -- it fits a standard kitchen counter with 12-inch depth clearance. The 18-cup footprint is slightly smaller. Both units are 10.4 inches tall, which fits under standard upper cabinets with 18-inch clearance above the counter. The Stream 10-cup pitcher is 10.5 inches tall and 5 inches wide -- smaller and lighter, easier to move to the refrigerator for chilled filtered water.
Step 5: Decide on Countertop vs. Connected System
All Brita gravity dispensers (Ultramax, Stream) are countertop units with no faucet connection. They deliver ambient-temperature water. If you want chilled filtered water, fill the dispenser from the tap and then refrigerate it -- neither the Ultramax nor the Stream chills water independently. The Brita Hub is the only Brita product that connects to a water supply line and delivers on-demand filtered water through a faucet without manual reservoir filling.