Tree has not been pruned, but yet it drops water constantly. It does this in several places. You can actually sit and watch it drip continuously. We thought it may be sap, but upon further investigation, it is truly water. No stickiness, no smell, no color. The plus side? Grass below the tree is green year round. What causes this?
Why Is My Walnut Tree Dripping Water?
Certified GKH Gardening Expert
Has this been happening year after year?
Does the tree otherwise look healthy? Are there deep cracks in the bark from which sap is oozing? Does the clear odorless liquid stain or discolor the tree bark? If there were cracks in the bark that oozed sap and if the bark was stained reddish or dark brown it could be a deep bark canker that affects walnut trees.
I think we can rule out slime flux because slime flux is usually foul smelling and not clear.
My gut feeling, however, is that your walnut tree is simply "crying" due to positive root pressure caused by the onset of warmer weather. The non-sticky, colorless and odorless liquid is actually sap, which is comprised mainly of water. Here is an excellent article that will explain what is happening in great detail: