Moats and Trenches

The typical moat, listed in Chapter 5 of the DUNGEON MASTER’s Guide, costs 50,000 gp. That gives you 500 linear feet of a channel 15 feet deep and 30 feet wide, with your choice of a wooden drawbridge or a permanent bridge of reinforced masonry.

If you want to customize your moat, build it in 10- foot linear sections. For each section, pay 100 gp for each 10-foot wide by 5-foot deep excavation. For example, a 20-foot-wide, 40-foot-deep moat costs 1,600 gp per 10-foot section.

The above costs assume normal earth. If your stronghold sits on particularly rocky ground, double the cost. If it sits on solid stone, multiply the cost by 5.

A typical bridge costs 5,000 gp. Table 2–8: Doors lists drawbridge prices. You can have water in your moat, or you can leave it as a dry trench.