Replastering a 20,000-Gallon Kidney-Shaped Pool With Waterline Tile: Full Cost Breakdown

You finally commit to replastering the pool, get a contractor on the phone, and the quote comes back with a number that makes you set down your coffee. If the kidney shape and that waterline tile band seem like they should be simple add-ons but the price keeps climbing, you are not imagining it - both factors genuinely affect the final bill in ways most ballpark estimates never explain.

Replastering a 20,000-gallon kidney-shaped inground pool with a waterline tile band costs $8,500 to $16,500 in total, depending on the plaster finish you choose, the tile material, and where you live. Standard white plaster with basic ceramic tile lands between $8,500 and $11,000. Premium pebble or glass bead finishes with designer mosaic tile can push past $16,000. This article breaks down every cost line - plaster materials, tile, labor, surface prep, and refill chemistry - so you know exactly where the money goes and what you can realistically negotiate.

What Drives the Cost on a Kidney-Shaped Pool Specifically?

Pool plastering is priced by surface area, not by volume. A 20,000-gallon kidney-shaped pool has roughly 1,000 to 1,100 square feet of interior surface (walls and floor combined), which is actually a bit more than a rectangular pool of identical volume. The curves on a kidney shape slow the hand-troweling process, so most crews add a 10 to 15 percent labor premium over a same-size rectangular job. That might sound small, but on a $10,000 project it is an extra $1,000 to $1,500 that does not appear on a per-square-foot quote until you look closely.

The waterline tile band is a separate trade entirely. Plaster crews set the plaster; tile setters install the tile. On many projects, those are two different subcontractors, which means two mobilization charges, two schedules to coordinate, and two sets of material markups. If your contractor handles both in-house, you save on coordination costs - worth asking about directly.

Cost by Plaster Finish Type

The single biggest lever on your total bill is the finish you pick. Here is how the main options stack up for a 20,000-gallon kidney pool:

Why These Differences Matter for Your Decision

White plaster costs least up front but tends to stain and etch within 7 to 10 years, especially if your water chemistry drifts. Quartz aggregate costs $2,000 to $3,000 more but lasts 50 percent longer - over two replaster cycles, you come out ahead on quartz. Pebble and glass bead finishes carry the highest material cost but also the longest lifespan, so they make the most financial sense if you plan to stay in the home for 15-plus years. If you are selling in three years, standard plaster makes the pool look fresh without overinvesting.

Waterline Tile Band: What It Actually Costs

A waterline tile band on a kidney pool runs the full perimeter of the pool at the waterline, typically a strip 6 inches wide. The perimeter of a 20,000-gallon kidney pool is roughly 90 to 110 linear feet. Here is what you can expect to pay by tile type:

• Standard 6x6 Ceramic Tile: $12 to $22 per linear foot installed, so $1,100 to $2,400 total for the perimeter. Durable, easy to clean, widely available in dozens of colors.
• Porcelain Tile: $20 to $35 per linear foot installed, or $1,800 to $3,850 total. More resistant to fading and chemical exposure than standard ceramic.
• Glass Mosaic Tile: $40 to $70 per linear foot installed, totaling $3,600 to $7,700. Visually striking but requires a skilled setter and adds significant labor time on curved walls.
• Hand-Painted or Custom Ceramic: $60 to $100-plus per linear foot. Reserved for high-end renovations; budget $5,500 to $11,000 for the perimeter alone.

For most owners, porcelain tile at $2,000 to $3,500 hits the sweet spot: it lasts 20-plus years, holds color well under UV exposure, and does not demand a specialty installer. Glass mosaic looks stunning but curves on a kidney pool mean more cutting, more waste, and more labor hours - that is where costs spike unexpectedly.

A Worked Example: Full Project Budget

Say your 20,000-gallon kidney pool measures roughly 40 feet by 25 feet at its widest points, with about 1,050 square feet of interior surface and a 95-linear-foot perimeter. You choose a quartz aggregate finish and porcelain waterline tile. Here is how the budget stacks up:

• Surface preparation (acid wash, chip existing plaster if needed): $600 to $1,200
• Quartz aggregate plaster - materials and labor: $8,500 to $11,000
• Porcelain waterline tile - materials and labor (95 linear feet): $1,900 to $3,325
• Equipment rental and site protection: $200 to $400
• Water fill and startup chemistry: $150 to $350
• Total estimated project cost: $11,350 to $16,275

A mid-range outcome - quartz plaster, standard porcelain tile, light prep work - lands around $13,000 to $14,000 for most homeowners in the continental U.S. Coastal markets (Florida, Southern California) and the Northeast can add 15 to 25 percent to those figures due to labor rates and permit costs.

What Gets Left Off the Quote (Watch for These)

Contractors are not always trying to low-ball you; some costs genuinely only appear once the pool is drained and inspected. Know these before you sign:

• Main drain replacement: If the main drain cover is not VGB-compliant or is cracked, most contractors will flag it as a code requirement. Budget $250 to $600 to replace it while the pool is empty.
• Return fitting and skimmer throat repairs: Cracked skimmer throats and deteriorated return fittings become obvious once the plaster is stripped. Repairs run $150 to $500 per fitting.
• Step refinishing: Integrated steps often need separate attention, especially if they use a vinyl bead insert. Factor in an extra $300 to $800 if your steps are showing wear - something we covered in detail in our post on pool replaster cost with a vinyl liner step and tanning ledge.
• Permits: Some municipalities require a permit for replastering. Fees range from $75 to $350 depending on the county.
• Water disposal fees: Draining 20,000 gallons to a municipal sewer (where permitted) sometimes carries a discharge fee of $100 to $300.

Startup Chemistry After Replastering

New plaster is alkaline and reactive. For the first 28 days, pH tends to climb fast, and calcium hardness needs to be raised carefully to protect the fresh surface. Target a pH of 7.4 to 7.6, total alkalinity of 80 to 120 ppm, and calcium hardness of 200 to 250 ppm during the startup period. Brushing the walls twice daily for the first two weeks prevents white calcium deposits from bonding to the new surface - skipping this step is the most common mistake new plaster owners make. AquaDoc's calcium hardness increaser is one product pool owners use during this startup window to hit that 200 ppm floor without overshooting.

Once the plaster has fully cured (around 28 to 30 days), the cost of ongoing maintenance goes up slightly because you are now protecting a more expensive surface. If your pool runs a heater, proper sizing matters here too - an undersized heater cycles on and off more frequently, creating temperature swings that stress fresh plaster; our pool heater BTU sizing guide walks through how to match heater output to pool volume so you avoid that problem.

Frequently Asked Questions

How much does it cost to replaster a 20,000-gallon inground pool?

Replastering a 20,000-gallon inground pool costs $6,500 to $13,500 for the plaster work alone, before adding waterline tile. Standard white plaster sits at $6,500 to $8,000 installed; quartz aggregate runs $8,500 to $11,000; pebble and glass bead finishes reach $10,500 to $13,500. Add $1,500 to $3,850 for a porcelain or ceramic waterline tile band, bringing most complete projects to $8,500 to $16,500 total.

How much does a waterline tile band add to replaster cost?

On a 20,000-gallon kidney pool with a 90 to 110 linear-foot perimeter, a waterline tile band adds $1,100 to $3,850 for ceramic or porcelain tile and $3,600 to $7,700 for glass mosaic tile. Labor to set and grout the tile on curved walls accounts for 40 to 50 percent of that cost. Porcelain tile delivers the best durability-to-cost ratio for most pools at $20 to $35 per linear foot installed.

How long does plaster last on an inground pool?

Standard white plaster lasts 7 to 12 years with well-maintained water chemistry. Quartz aggregate finishes typically last 12 to 18 years, and pebble finishes can last 20 to 25 years. Keeping pH between 7.4 and 7.6 and calcium hardness between 200 and 400 ppm has the single biggest impact on how long any plaster finish holds up.

How long does replastering a kidney-shaped pool take?

The replaster process itself takes 3 to 5 days: one day for draining and surface preparation, one to two days for plaster application, and one to two days of curing before the fill begins. Refilling a 20,000-gallon pool takes 24 to 48 hours depending on water pressure, and startup chemical balancing adds another day or two. Plan for roughly one week of total downtime.

Does the irregular shape of a kidney pool make replastering more expensive than a rectangular pool of the same volume?

Yes, by roughly 8 to 15 percent in labor. Curved walls require more hand-troweling time and slower finishing passes than flat rectangular walls, so most crews price kidney pools slightly higher per square foot. On a $10,000 project that difference runs $800 to $1,500 - real money, but not enough to steer you toward a rectangular pool if a kidney shape is what you have or want.

A 20,000-gallon kidney pool with a waterline tile band is a mid-to-large renovation, and the numbers reflect that: budget $8,500 at the low end for white plaster with basic ceramic tile, and up to $16,500 or more for a premium pebble finish with glass mosaic. Knowing each cost line before you call contractors puts you in a much stronger position to compare quotes accurately.

If you have questions about the water chemistry side of a replaster startup - or anything else about keeping your pool in good shape - we are happy to help. AquaDoc carries pool chemicals and balancing products for every phase of pool ownership, from the day you refill after a replaster to the end of the season.