The cost of maintaining a pool depends on a number of factors, including where you live, the type of material your pool is constructed from, how you use your pool, and how large it is. Fiberglass inground pools are relatively inexpensive to maintain because their nonporous finish deters algae growth, requiring fewer chemicals and elbow grease to keep it clean. Additionally, fiberglass does not require regular resurfacing, unlike vinyl and concrete pools. In general, you can expect to pay between $350 and $400 a year maintaining your fiberglass pool. This is significantly cheaper than the cost of maintaining a vinyl or concrete pool, which typically costs over $1000/year.