A portable spa unit is self contained. This means everything needed to operate it is included within the spa itself, which is partially what makes them so cost-friendly. It also means that wherever it is positioned, water from the rain must be free to drain away from the hot tub. If it can’t escape, the plumbing could get damaged. So when positioning it in-ground, the hot tub plumbing equipment needs to be removed and protected above ground, where it is also accessible for any future repairs or adjustments. www.besthottubs.com