We’ve found sometimes it can appear there is a leak when really there isn’t. Notice when you fill your bottle if water is pouring down the side. If it is, that water can collect in the base and then when you take a sip the base will empty making you think you have a leak. Not spilling while filling the bottle will relieve this issue. In addition, sometimes after cleaning or reassembling your bottle the silicone ring in the base of the bottle may not sit properly. In this case, disassembling and then reassembling your bottle will often relieve the issue.