Lake Wartook sits within the Grampians National Park in Victoria's western district, roughly 30 minutes from Halls Gap and approximately three hours from Melbourne via Ararat. The lake is formed on the MacKenzie River and holds the distinction of being the oldest irrigation storage in Australia. It serves as the primary water supply for Horsham and Natimuk, as well as Supply System 6 of the Wimmera Mallee Pipeline, which has direct implications for permitted activities on the water.

Paddling, sailing, and motorised boats are all permitted, though a strict speed limit applies — either 5 or 8 knots depending on the authority, so paddlers should confirm the current limit with GWMWater, the boating authority for the lake. Motors up to 10 hp are permitted. Swimming is not allowed. Dogs are not permitted at the lake, and campfires are prohibited. A boat ramp is located near the dam wall and is suitable for vessels up to 5 metres when the lake is at capacity; access is via a gravel road.

The lake is large and surrounded by the sandstone ranges of the Grampians. The water is generally clear for most of the year with a slight tannin stain from drowned timber. Submerged tree stumps are a genuine hazard, particularly when water levels are low, and paddlers should exercise caution throughout the lake. A small island called Bear Island sits just east of the centre of the lake. The eastern side is shallower with extensive weed beds, while the area near the dam wall is considerably deeper. Bank access is limited in many areas due to dense vegetation reaching the water's edge, though a rough track along the western side provides a few access points.

The lake is popular for trout fishing — both rainbow and brown trout are present — as well as redfin perch. Fishing activity, including boats trolling lures, is common and worth accounting for when planning a paddle. Nearby facilities include a picnic area at the dam wall and a campground approximately 5 kilometres from the lake with pit toilets. Reeds Lookout offers elevated views over the lake for those exploring the surrounding area on foot.