For best results, place your rain gauge at least 20' from buildings, trees or other obstructions. Try to keep it as straight as possible.

Be sure the foam float is in place, even with the bottom of the measurement tube. 

Occasionally rinse out the measurement tube and copper flute. You can clean the blue tube and the inside of the flute with warm, soapy water. Rinse thoroughly before putting it back outside.

Want a shiny, fancy-looking copper flute? You can use copper polish to shine your rain gauge.

If the tube is not rising, check the following:

Has the foam float deteriorated? That can happen sometimes. You'll need to replace it. Don't worry; it's easy to do. Watch this video to learn how to replace the foam. Easy, right? Order the parts here. 

Is there debris of any kind in the tube? Mold, dirt and other funk can impede the smooth operation of the rain gauge. Use a bottle brush to clean the inside of the tube. Do not use WD-40 or other lubricants inside the rain gauge!

Is the gauge leaking? Fill the flute with water and set it in the sink. If the water is leaking around the seal at the bottom or if, more obviously, the cap is missing entirely, you need to replace the end cap. Here's what you need to fix that.