Check the potting medium to see if it is completely dry by sticking your finger 1 inch deep into the soil. If it is damp, do not water yet and check again the next day. If it is dry, it needs to be watered.
Place the orchid in the kitchen sink. Water thoroughly with lukewarm water until the water runs freely from the drainage holes for a minute. Avoid watering with cold water and distilled or salt-softened water.
Check to see if any water is on the leaves or at the crown of the cattleya. Dry with a paper towel to avoid crown rot.
Let the water drain completely before placing the cattleya orchid back in its location in your home.