How Much Does Main Water Line Repair Cost in Seattle?

Main water line repair costs in Seattle average $2,254, and most homeowners pay somewhere between $859 and $3,804. The length of the piping you need to repair and the type of damage are the most influential cost factors. However, the pipe’s materials and accessibility play important roles, too. 

Main Water Line Repair Cost Factors

Homeowners in Seattle pay as little as $350 for main waterline repairs, and prices can climb as high as $5,200 in extreme cases. You should consider all of the following factors to get the most accurate estimate possible for your project.

Linear Feet

The length of the pipe you need repaired or replaced is the most significant cost factor to consider, as you can expect to pay $100 to $200 per linear foot. The average lot size in the Seattle metropolitan area is just 5,200 square feet, so the length of pipe you could need repaired is significantly shorter than you’d find in most other areas.

Type of Damage

The type of damage your water main is suffering from will play an important role in how much of your main line your plumber needs to repair. A local plumber can help you determine the underlying cause, which can help you estimate the cost.

Many water main issues in Seattle result from seismic activity, which causes sudden shifts in the soil that can crack water mains. Damage from an earthquake is usually localized and should cost between $850 and $1,500 to repair.

A more severe problem is corrosion, which is also common in Seattle, thanks to the very soft water. Soft water pulls minerals away from your piping and gradually deteriorates the material. If corrosion is your underlying water main issue, you’ll likely need to replace a larger section of your water main, and your total will sit closer to the $2,000 to $4,000 range.

Materials

Most main water lines in Seattle are made from ductile iron, which has repair costs that sit between PVC and copper, often between $2 and $10 per linear foot for materials alone. Ductile iron stands up well to seismic activity, although it’s prone to corrosion from Seattle’s soft water.

PVC costs 25% to 50% of that and is resistant to corrosion, but it’s more likely to crack from seismic activity. Copper is the most expensive, at triple the price of ductile iron. It resists corrosion well but will crack more easily during earthquake activity, so it’s an uncommon choice in Seattle.

The table below includes material prices for these options only. Keep in mind that labor makes up a much bigger portion of your total.

Accessibility

Water main lines are located underground, and the bulk of your total will go toward excavation to expose the damaged line. To prevent bursting, water mains need to sit below the frost line, which is the depth at which the ground no longer freezes in the winter. The average frost line depth in Seattle is 18 inches, so you’ll need quite a bit of excavation to expose the piping.

Your main water line repair costs can increase by thousands if your professional needs to break up sidewalks, concrete pathways, driveways, decks, or other landscaping features to access the damaged main line.

Plumber Costs

The labor cost of hiring a plumber in Seattle for a water main line repair averages $2,000 and accounts for 90% of your total. Most of that will go toward excavation to access the line, and the rest will go toward the actual plumbing repairs.

In addition to labor fees, you’ll need to pay a plumbing permit fee to your plumber, which your pro will then pay to the local building department to legalize your repairs. The City of Seattle charges a flat rate of $132 for a plumbing permit, so be sure to budget for that in addition to the actual work.

Does Main Water Line Repair Increase Home Value?

Main water line repair won’t increase your home value, but it can prevent a loss of value if it helps avoid property damage and unusually high water bills caused by underground leaks.

Since the water main is buried, even a full replacement won’t add much to your home value, as it won’t affect curb appeal at all. Buyers may see a full main water line replacement as a good sign that they won’t have to lay out money for repairs or a replacement after closing, but if they’re willing to pay more for that peace of mind, it likely won’t be much.

How Angi Gets Its Cost Data

Home is the most important place on earth, which is why Angi has helped more than 150 million homeowners transform their houses into homes they adore. To help homeowners with their next project, Angi provides readers with the most accurate cost data and upholds strict editorial standards. We survey real Angi customers about their project costs to develop the pricing data you see, so you can make the best decisions for you and your home. We pair this data with research from reputable sources, including the U.S. Bureau of Labor Statistics, academic journals, market studies, and interviews with industry experts—all to ensure our prices reflect real-world projects. 

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