Waterfalls and water fountains soothe the soul. Water in your basement stirs up anguish.

There are several methods to keep water out of your basement or remove what gets in. The most expensive, as well as the most effective, can require extensive excavation, our researchers learned in interviewing homeowners and highly rated contractors.

Interior solutions

Interior-based waterproofing methods, often called “negative side” projects, involve moving out water that’s inside the home.

Fixing a water problem from the inside may be a cheaper option, especially in cases where exterior work isn’t practical or possible.

Drain: This system moves water out of the house through a hole or trench in the foundation, paired with a sump pump. Such a system should also include insulation of basement walls, with a vapor barrier to protect against condensation. Drainage systems start at around $2,000.

Sealants: Some highly rated waterproofing companies don’t recommend sealants because they say they fail too easily. The cost of a sealant-based waterproofing project may range from $4 to $8 a square foot.

Epoxy injection: Like sealants, this option is not always favored because it may provide only a temporary solution to fill cracks in poured-concrete walls. Epoxy injections can start at $300.

Exterior solutions

Exterior waterproofing projects are sometimes called “positive side” jobs because the aim is to prevent water from getting in the house.

Excavation: Many contractors consider installing an underground trench or perimeter drain to be the most effective method, if done correctly. However, the average range for an excavation job is $20,000 to $30,000, and can be as high as $80,000, depending on how accessible the targeted areas are, how much digging is required and how much landscaping or other work must be restored.

Sodium bentonite: Some waterproofing contractors don’t like this method of adding a clay material to the dirt around the home to fill cracks and absorb water. They say it’s a temporary solution and difficult to control, since the clay can clog outdoor drains. Costs for this method start around $500.

Before you hire

• First try the simplest solutions, such as making sure gutters are free of debris, downspouts are moving water 20 to 30 feet from the foundation and the property slopes away from the foundation.

• In addition to using a trusted online site to review local consumers’ experiences, consider contractors who belong to the Basement Health Association, a trade organization that offers certification and continuing education. Also, get multiple bids, check references and make sure that the company you hire is properly licensed, insured and bonded.

• Beware of a prospective contractor who repeatedly offers to lower the estimated price. Also, be aware that waterproofing work is often calculated by the linear foot. Be sure to get all relevant details, including price, in writing.