Swale

A swale in golf is a shallow, grass-covered dip in the ground, usually found beside a green or running across a fairway. A ball that reaches one gathers at the bottom, leaving a recovery shot from below the level of the target.

What is a swale in golf?

A swale is ground that falls away and then rises again. The surface stays grass, the turf is mown and playable, and no sand or stakes mark it off. That is what separates a swale from the other low ground on a golf course.

Size varies enormously. Some swales are a gentle depression of a foot or two that a player barely registers until a putt breaks the wrong way. Others swallow people whole. The Valley of Sin, the hollow at the front of the 18th green on the Old Course at St Andrews, sits roughly eight feet below the putting surface, according to Golf Digest.

The word was borrowed from land drainage, where a swale is a shallow channel that carries surface water away. Merriam-Webster still lists both senses, and the older one explains most of what the feature does on a golf course.

For the player, the consequence is straightforward. A ball in a swale sits below the hole, usually on a tight lie, and the next shot has to travel uphill before it does anything else.

Why golf courses have swales

Drainage comes first. Water runs downhill and collects in low ground, so architects shape swales deliberately to route it away from the surfaces that matter. Most greens are built with two of them, according to Golf Course Industry: one exiting the front of the green and a second draining the back portion toward the natural low side. The front swale is kept gentle, close to the 1.5 percent minimum slope needed for water to move at all. Larger greens with three tiers may need a third swale, though on a mid-size green that third channel should carry only 5 to 10 percent of the surface, or it creates a crown in the middle that rejects good shots.

Strategy is the second reason. A swale beside a green gathers balls that finish a yard or two off line and pulls them further from the hole than rough would. The USGA Green Section notes that closely mown green surrounds are cut at or below fairway height, and that this height of cut decides how far a ball rolls away and which recovery shots are realistic. Cut too high and balls hang up on the slope. Cut too low and everything funnels to the same spot.

Where swales appear on a course

Greenside is the most common position. Balls that catch the edge of a crowned green feed down into the surrounding low ground, which is exactly how Pinehurst No. 2 defends itself: Golf Club Atlas describes greens that shed balls into swales and hollows the golfer never intended to visit.

Some swales sit directly in front of a green, forcing an approach to carry all the way. The Valley of Sin is the famous one. Costantino Rocca holed a putt from inside it in 1995 to force a play-off with John Daly at the Open, which tells you the recovery is difficult rather than impossible.

A swale can also cut through the putting surface itself. That is the defining feature of the Biarritz, a template hole popularised in America by architect C.B. Macdonald. LINKS Magazine describes the classic version as a long par three of 210 to 240 yards with a swale three to five feet deep running across the green. Finish on the wrong side of it, and the putt has to travel down one bank and up the other.

Fairway swales are easier to miss from the tee. Rolling ground creates low points where a decent drive can finish, and those low points are where water tends to collect.

Swale vs. bunker, hollow and collection area

Golfers use several words for low ground, and they overlap enough to cause confusion.

Feature	What it is	Surface	Rules status
Swale	A shallow dip or channel in the ground, often elongated	Grass, cut anywhere from putting height to rough	General area; play the ball as it lies
Hollow	A smaller, more bowl-shaped depression	Grass	General area; play the ball as it lies
Collection area	Any low ground beside a green that gathers balls	Grass, usually fringe or fairway height	General area; play the ball as it lies
Bunker	A prepared depression filled with sand	Sand	Separate category under Rule 12; the club cannot be grounded

The difference between a swale and a hollow is mostly one of shape and scale. A hollow is a pocket. A swale tends to run, which is why the drainage sense of the word survives.

Collection area describes what the ground does rather than what it looks like. A greenside swale mown at fairway height usually is one. Golf Compendium notes that these areas spread through American golf as designers copied the tight lies of British links, replacing deep greenside rough with short grass below the putting surface. Architects also use the term fringe swale, which Top 100 Golf Courses applies to shortgrass sitting beneath the level of the green, whether or not it forms a true valley.

The bunker is the clear outlier. Sand changes both the shot and the rulebook.

What the rules say about a ball in a swale

A swale is part of the general area of the course, which means it carries no penalty and no free relief. The ball gets played as it lies. Nothing about a dip in the ground entitles a player to move it.

Water changes that. Temporary water, called casual water before the 2019 rewrite of the Rules of Golf, is an abnormal course condition, and Rule 16.1 gives free relief when it interferes with the ball, the stance or the swing. Since swales exist to collect water, they are where puddles show up first after rain.

The bar is higher than wet turf, though. An accumulation of water has to be visible before or after the player takes a stance. Sam Burns learned how strictly that gets applied at the 2025 U.S. Open. Tied for the lead on Oakmont’s 15th hole after a 96-minute rain delay, his tee shot finished in the lowest part of the fairway. Two USGA officials turned down his request for relief, he played from the wet lie into thick rough, and made double bogey. ESPN reported that his practice swings were throwing up spray each time.

One further exception applies. A ball plugged in its own pitch mark gets free relief under Rule 16.3 anywhere in the general area, which covers soft low ground after heavy rain.

Related Golf Terms

Run-off area — A slope that feeds missed shots away from the green.
False front — A sloping front edge of a green that rejects short shots.
Punchbowl green — A green set in a bowl-shaped depression that gathers shots.
Undulation — The rolls, slopes, and contours across a green or fairway.
Double green — A single large green shared by two different holes.

Frequently Asked Questions

Is a swale a hazard in golf?

No. A swale is grass-covered ground in the general area of the course. Bunkers and penalty areas are the two categories that carry special rules, and a swale is neither.

Can you get relief from a swale?

Not from the dip itself. Free relief is available only if something else interferes, such as temporary water pooling at the bottom or a ball embedded in its own pitch mark.

What is the difference between a swale and a bunker?

Grass versus sand. A bunker is a prepared depression filled with sand and governed by Rule 12, which forbids grounding the club. A swale is turf and plays like any other part of the general area.

How deep is a swale?

There is no standard. Subtle ones measure a foot or so. The swale on a classic Biarritz green runs three to five feet deep, and the Valley of Sin at St Andrews drops around eight feet below the green.

What is a Biarritz swale?

The deep channel that crosses the middle of a Biarritz green, splitting it into front and back sections. C.B. Macdonald brought the design to America after seeing the original hole in France.

Why do greens have swales around them?

Two reasons at once. They carry surface water off the putting surface, and they gather off-line approach shots into a spot that demands a delicate recovery from a tight lie.

Sources

Merriam-Webster. “Swale.” Accessed August 2026.
https://www.merriam-webster.com/dictionary/swale
Cambridge Dictionary. “Swale.” Accessed August 2026.
https://dictionary.cambridge.org/us/dictionary/english/swale
USGA Green Section Record. “Establishing and Maintaining Closely Mown Green Surrounds.” Volume 61, Issue 10. Accessed August 2026.
https://www.usga.org/content/usga/home-page/course-care/green-section-record/61/issue-10/establishing-and-maintaining-closely-mown-green-surrounds-.html
R&A and USGA. The Official Rules of Golf, Rule 16 (Rules 16.1 and 16.3). Accessed August 2026.
https://www.randa.org/en/rog/the-rules-of-golf/rule-16
Golf Course Industry. “Getting Back-to-Front Green Slope Right.” Accessed August 2026.
https://www.golfcourseindustry.com/article/getting-back-to-front-green-slope-right/
Golf Digest. “15 St. Andrews Landmarks You Need to Know.” Accessed August 2026.
https://www.golfdigest.com/story/british-open-2022-st-andrews-landmarks-swilcan-bridge-hell-bunker-old-course
LINKS Magazine. “12 of the Best Biarritz Holes in the U.S.” Accessed August 2026.
https://linksmagazine.com/12-of-the-best-biarritz-holes-in-the-u-s/
GOLF.com. “What Is a Biarritz? And How Can Identifying One Help Your Game?” Accessed August 2026.
https://golf.com/travel/what-is-a-biarritz-and-how-can-identifying-one-help-your-game/
Golf Compendium. “Explaining the Golf Course ‘Collection Area’.” Accessed August 2026.
https://www.golfcompendium.com/2021/03/collection-area-golf-definition.html
ESPN. “Sam Burns Denied Casual Water Relief, Double-Bogeys 15 at U.S. Open.” Accessed August 2026.
https://www.espn.com/golf/story/_/id/45521174/sam-burns-denied-casual-water-relief-double-bogeys-15th-hole-us-open
Golf Club Atlas. “Pinehurst (No. 2).” Accessed August 2026.
https://golfclubatlas.com/countries/pinehurst-no-2-2/