Incoming water, outgoing water, and the outlet
Lai shui is the water arriving. It should come from a wide, open direction and arrive slowly. Qu shui is the water leaving. It should leave through a narrow gap and be hard to see from the site. That gap is the shui kou, the outlet. It is the one thing a form school master checks first. A tight outlet, closed by hills or a bend, means the valley holds. A wide open outlet means whatever the hills gathered drains straight away. The Tianxing school then reads the outlet's direction on the luopan against the twenty-four stars, which is where the facing is later decided.
Belt water, bow water, pooling and shooting
Yu dai shui, jade belt water, curves around the site. The site sits on the inside of the bend. This is the best shape: the bank on the inside builds up and the current slows.
Fan gong shui, reverse bow water, is the same bend seen from the other side. The site sits on the outside, where the current cuts the bank. The bow is drawn at you.
Ju shui is water that pools in front: a pond, a lake, a wide slow reach. Straight water that runs directly at the site, or directly away from it, is called shooting. It neither gathers nor holds.
What this means on the ground
For a grave, find the outlet first. Work out which way the ground drains and follow it to where the water leaves the valley. If you can see that point clearly and it is wide, the site leaks. If it is hidden behind a hill or a turn, the site holds.
For a house or a shop, the road is the water. A road that curves around the front of the building, with the building on the inside, is belt water. A road that curves the other way, or a T junction aimed at the door, is bow water or shooting water.
Common mistakes
The first mistake is to judge water by its beauty. A clear, fast stream running straight past the plot is pretty and useless. Slow, curving water that pools is what the form school wants.
The second is to forget the outlet. People look at the water in front and never ask where it goes. If the outlet is wide and visible, the rest does not matter much.
The third is to ignore roads. The road in front of the house or shop does the work of water, and a road aimed at the door is read exactly like a stream aimed at a grave.
Questions people ask
What does water mean in feng shui?
The river, stream, pond or road a site faces. The form school reads where it comes from, where it leaves and what shape it makes in front, outlet first.
Is a road in front of my house bad feng shui?
It depends on the shape. A road curving around the front with the house on the inside is belt water, good. A road or junction aimed at the door is shooting water, poor.
What is a water outlet (shui kou) in feng shui?
The point where water leaves the valley or the site's view. A narrow, hidden outlet holds the site; a wide, open one drains it. It is the first thing a master checks.
If a river or a road sits in front of the plot you are considering, book a site reading and have the water read properly before you commit.