6 Tips to Make Your In-Ground Pool Installation Go Swimmingly

There are few home features that can create as much fun and excitement as an in-ground swimming pool. It can instantly transform any boring backyard into a sun-splashed oasis, which people of all ages can enjoy. And while in-ground pool installation requires a significant investment of both time and money, their popularity isn’t waning any time soon. According to the nonprofit Pool and Hot Tub Alliance, based in Alexandria, Virginia, there are over 5 million existing in-ground pools in the U.S., and nearly 200,000 new pools are built each year.

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So, if you’re ready to take the plunge and install your own in-ground swimming pool, here are six key steps to get you toward your dream pool.

There are three main types of in-ground pools. In order of popularity they are: concrete, vinyl-lined, and fiberglass. In small pockets of the country, you might also find steel- or aluminum-walled pools.

All three types of pools—concrete, vinyl and fiberglass—are available nationwide. However, some types are more prevalent than others in certain regions. The flexibility of fiberglass and vinyl liners makes them ideal for cold climates, where freezing and thawing cycles can damage a rigid concrete structure. Vinyl pools are sold in most areas, while fiberglass is most popular in the south.

If you’re not sure which type of pool to get, rely on the expertise of local pool contractors. If they’re primarily installing one type of pool, there’s probably a very good reason why. (It often has to do with the local climate and soil conditions.) Once you decide on the type of pool you want, be sure to hire a contractor with extensive experience installing that particular type.

→ Concrete pools

Concrete pools are truly custom-built, and can be formed to virtually any size, shape, or depth. These pools are often called “Gunite” or “Shotcrete” pools because concrete is shot from a gun onto steel-reinforced walls. Once the concrete cures, the pool is either tiled or plastered, painted, and finished with a textured surface.

It takes longer to install a concrete pool than any other kind (generally between three and 12 weeks), but it’s the strongest, most durable type of pool. In fact, there are many concrete pools still in use today that are well over 50 years old! And, unlike other types of in-ground pool, existing concrete pools can be remodeled, enlarged, and updated.

→ Vinyl pools

Vinyl pools are made from a preformed flexible liner that fits into the excavated hole. It’s secured to a reinforced frame made of steel, aluminum, or non-corrosive polymer. A vast majority of vinyl pools are rectangular, but L-shaped and freeform liners are available from some manufacturers. Construction time for building a vinyl-lined pool is generally one to three weeks.

When considering a vinyl pool, be aware that pool toys, pets, and sharp objects can puncture the liner. And while liners can be repaired, it’s best to choose one that’s at least 20–30 millimeters (about ¾–1 inch) thick.

→ Fiberglass pools

Fiberglass pools are factory-molded into one giant bowl, which a crane sets into the excavated hole. As a result, fiberglass pools can be installed much more quickly than other pool types—in some cases, in as little as three days. Fiberglass pools have a super-smooth gel coat finish that’s extremely durable and stain resistant. And unlike concrete pools, fiberglass is nonporous, so it uses fewer pool chemicals and harbors less algae.

However, fiberglass pools come in fewer sizes and shapes than concrete or vinyl pools, which might be an issue if you’ve got a small or uniquely shaped backyard. And the huge molded pool must be shipped via truck, which might be forced to take a long, circuitous route to your house; that’s because the transportation of oversized loads is regulated by individual states, and truckers often have to drive around several states to deliver a fiberglass pool.

Once the pool arrives, there must be adequate space in your yard for the crane to drive close to the site and maneuver the molded shell into the excavated hole. Note that access is sometimes only available through a neighboring property. Be sure to check with the trucking company or pool contractor to confirm that there’s enough space for the crane to operate.

It’s impossible to say precisely how much your pool will cost, since prices vary widely depending on where you live, soil conditions, water-circulation systems, and the type and size of the pool. The time of year can also influence the final price, since many contractors offer discounts for pools built during the off-season when business is slow.

Generally speaking, concrete pools are the most expensive, followed closely by vinyl-lined pools, and then fiberglass. However, a high-end, tricked-out fiberglass pool could cost more than a barebones concrete pool.

In New England, where I live, a simple rectangular 20-by-40-foot concrete pool costs about $45,000, including the filtration system, initial water fill-up, underwater lights, and stone coping around the pool’s edge. That does not include the cost of the fencing, landscaping, decking, and other pool-related items you might need to consider. Keep in mind that most homeowners spend about twice the pool cost to complete their swimming pool project. So, if you buy a $50,000 pool, be prepared to spend an additional $40,000–$50,000 before all is said and done.

In-ground swimming pools are subject to building and zoning regulations, so you must apply for a building permit and receive approval before any work can begin.

Building and zoning rules differ from town to town, but ordinarily you must satisfy certain setback distances from the pool to property lines, septic tanks, wells, sewer lines, and wetlands. There are also codes concerning pool barriers and gate hardware.

Generally, a perimeter wall or fence must be at least 4 feet tall and equipped with self-closing, self-latching gates. Fence boards or balusters must not be spaced more than 4 inches apart. Chain-link fences must have openings no larger than 1-1/4 inches wide.

For an extra level of protection, especially if you’ve got young children or grandchildren, consider mounting alarms on all house doors and gates leading to the pool, and installing a power safety cover over the pool. For a list of specific rules and restrictions, contact the local building department or zoning board.

Picking the best place for your pool is as important as deciding on the type of pool itself. An experienced pool contractor can provide valuable insight, but be sure to consider the following pool-placement tips:

• Capture the sun: Take advantage of free solar energy by choosing a pool location that’s open to the sun and well away from any trees. Such a location will not only warm up the water, it’ll also reduce the number of leaves that drop into the pool.

• Block breezes: Building a pool in a windy location greatly increases water evaporation, which means you’ll have to keep adding water to maintain the proper level. Strong winds can also make you feel uncomfortably cool when wet. Create a windbreak by erecting a solid-board fence, or by planting a row of thick shrubs.

• High and dry: Don’t set the pool in a low-lying area, which could result in the pool flooding with mud and debris during periods of heavy rain.

• All clear above and below: The pool shouldn’t be located beneath overhead telephone or electrical wires, or directly over buried sewer lines, septic systems, or electrical cables.

• Keep eye contact: Whenever possible, build the pool within view of the house. That way, you can keep an eye on swimmers even while you’re indoors.

→ Circulation Systems

A pool’s circulation system uses both filtration and sanitization to keep the swimming water clean and crystal clear. The filtration pump draws water from the pool’s bottom drains, sends the surface water through an automatic skimmer, and then passes everything through a filter before re-circulating back into the pool. There are three types of filters commonly used: sand, cartridge, and diatomaceous earth (DE).

All three types of filters work well when properly installed and well-maintained, and an experienced contractor will help you decide which filtration system is best for your pool.

• Sand filters are the oldest and most common method of pool-water filtration. They use special filter sand to trap dirt and debris. As the sand particles “load up” or become clogged, they trap smaller and smaller particles. Sand filters are cleaned by backwashing, which involves reversing the water flow through the filter, and flushing the dirty water into a waste line.

• Cartridge filters use large, cylindrical cartridges to screen out dirt. Most pool builders recommend using cartridges with 500–600 square feet of filter area. Unlike sand filters, cartridges don’t require backwashing. Instead, you simply rinse them off with a garden hose, a process that uses much less water than backwashing.

• Diatomaceous earth is a porous powder that has microscopic openings, similar to tiny sponges. As water passes through the openings, particles are trapped. DE filters can strain out dirt, dust, algae, and some forms of bacteria. When DE filters become dirty, they’re cleaned by backwashing, but use far less water than sand filters. Afterward, fresh DE is added to the filter.

→ Sanitizers

The pool’s water-filtration system removes debris, but a chemical sanitizer is needed to kill organic contaminants, such as bacteria and algae. And an oxidizer is used to kill both inorganic and organic contaminants. There are three EPA-registered sanitizers commonly used in swimming pools: chlorine, bromine, and PHMB.

• Chlorine is by far the most commonly used pool sanitizer; it’s also an effective oxidizer. When dissolved in water, chlorine releases free-available chlorine, also known as hypochlorous acid. There are different kinds of chlorine sanitizers available, including cal hypo, dichlor, gaseous chlorine, liquid chlorine, lithium hypochlorite, and trichlor.

• Bromine (hypobromous acid) tablets can also be used as a pool sanitizer. The solid white tablets slowly dissolve to produce free-available bromine, which is also a strong oxidizer.

• PHMB (polyhexamethylene biguanide) is a pool sanitizer that’s used in conjunction with hydrogen peroxide and an algaecide. Hydrogen peroxide is used as an oxidizer.

Salt-chlorine generators represent the latest advancement in pool sanitization. Instead of using standard pool chlorine, this system transforms common table salt into chlorine. Contrary to what you may have heard, salt chlorine generators don’t create saltwater swimming pools.

Note that it’s important to test the pool water before adding any chemicals. Take a water sample to a local pool store for analysis, or buy a do-it-yourself test kit. Maintain the pH between 7.2 and 7.8, and keep the alkalinity between 80 and 120 parts per million. And during long stretches of very hot weather, be sure to test the water several times per week to maintain the proper balance.

As mentioned earlier, the final price of in-ground pool installation is usually about twice the cost of the pool itself. That’s because there’s so much more to an in-ground pool than a hole filled with water.

Here’s a list of items that aren’t typically included in the price of the pool: outdoor lighting, landscaping, pathways, decks, fencing, patios, privacy screens, whirlpool spas, outdoor sound systems, pool covers, water test kits, shade structures, patio furniture, equipment sheds, storage cabinets, pool toys, and additional outdoor electrical outlets.

You’re not likely to need all of these items, but keep them in mind when formulating your construction budget.

Joseph Truini

Joe is a former carpenter and cabinetmaker who writes extensively about remodeling, woodworking, and tool techniques. He has written eight books and is a contributing editor to Popular Mechanics. He also appears on the Today’s Homeowner TV show, and co-hosts the weekly Today’s Homeowner Radio Show. Joe writes from his home in Roxbury, Connecticut.