No water evaporation?

[sphelps]

The amount of evaporation is related to your homes relative humidity, the lower your humidity the more evaporation you should expect. Perhaps when you were noticing 5 gallons it was cooler outside which means relative humidity will typically be lower in your home unless you're running a humidifier fairly aggressively. With the warmer weather lately and the amount of rain we're getting relative humidity is much higher now that a few months ago.