Pond cost2026-10-03

How much does a backyard pond cost by size?

A professionally built backyard pond on the common 8 by 11 foot kit footprint is quoted anywhere from $4,400 to $16,000 in published cost guides and contractor price lists, an 11 by 16 foot pond from $8,670 to $25,000, and a 21 by 26 foot pond from $27,300 to $85,000. The national averages those guides lead with disagree by a factor of three ($3,382 at HomeAdvisor, $9,000 at Fixr, $10,500 at LawnLove), and the per square foot figures run from $14 to more than $220, because a koi pond dug 3 to 4 feet deep moves up to twice the soil, needs up to about 60 percent more liner and stacks far more rock than a 2 foot ecosystem pond on the same footprint. Depth, rock and filtration set the price more than the footprint does, so the useful first step is to know your own gallons and liner size before anyone quotes.

What the published cost guides say

No manufacturer or extension source publishes an installed price for a backyard pond. The only manufacturer number in this market is the kit price: Aquascape's Small Pond Kit 8 by 11 lists at $2,733.60 for a finished pond of "8 x 11 x 2 feet (LxWxMax Depth)" (Marquis Water Gardens listing), the Medium Pond Kit 11 by 16 at $4,484.76 and the Large Pond Kit 21 by 26 at $6,804.18 (Whiz-Q Stone). Everything else below is a cost guide or a contractor's own price list, and the guides borrow from each other. Fixr, Bob Vila and Grass Roots Pond & Garden publish the identical table (4 by 6 feet at $3,500 to $5,000, through 26 by 26 feet at $35,000 to $50,000), so three of the top results are one set of numbers.

Installed price by footprint, as published. Aquascape kit prices are parts only. Fixr, Bob Vila and Grass Roots share one table; their largest row is 26 by 26 feet.
Footprint	Aquascape kit, parts only	LawnLove, general pond	LawnLove, koi pond	Blue Thumb, professional	Fixr, Bob Vila, Grass Roots
8 by 11 feet (88 sq ft)	$2,733.60	$7,350 to $10,000	$4,400 to $11,440	$7,500 to $16,000+	$12,000 to $16,000
11 by 16 feet (176 sq ft)	$4,484.76	$8,670 to $14,500	$8,800 to $22,880	$12,000 to $25,000+	$13,000 to $25,000
16 by 21 feet (336 sq ft)	not sold	$14,165 to $20,335	$16,800 to $43,680	$20,000 to $40,000+	$25,000 to $35,000
21 by 26 feet (546 sq ft)	$6,804.18	26 by 26: $19,335 to $27,000	$27,300 to $70,980	$30,000 to $60,000+	26 by 26: $35,000 to $50,000

The headline averages do not fit those tables well. HomeAdvisor (updated June 17, 2026) says "The average cost to build a pond is $3,382" and "Professional pond installation costs between $1,221 and $5,669". Bob Vila (updated April 13, 2023) gives "a national average cost of $3,346", below its own cheapest row of $3,500 to $5,000 for a 4 by 6 foot pond, and adds "$40 to $60 per square foot for small to medium ponds." Fixr (updated August 18, 2022) puts the average at $9,000 for "a 6 x 8-foot koi pond with a rubber liner and complete landscaping". LawnLove gives a koi pond "National average cost $10,500" and "$50 to $130 per square foot", while its general pond page gives "National average cost: $7,400" and notes that "a Koi pond will need an area of at least 3 feet deep". Blue Thumb explains its spread: "Larger ponds need more liner, more underlayment, more rock, more gravel, larger pumps, stronger filtration, and more time to install."

Angi and HomeGuide refuse automated fetches, so their figures come from search snippets. The Angi koi snippet reads "between $14 and $50 per square foot" with tiers of 6 by 8 by 3 feet at $3,000 to $6,000, 10 by 15 by 3.5 feet at $6,000 to $12,000 and 15 by 20 by 4 feet at $12,000 to $25,000. The HomeGuide snippet reads "$2.50 to $9.00 per square foot", an excavated farm pond figure that does not describe a lined backyard build.

What contractors publish and what owners report

Regional builders post their own numbers, and they land above the aggregators almost everywhere. Grass Roots Pond & Garden (New Boston, Michigan) uses the shared table above and says "The deeper the hole, the more expensive it will be to dig." Superior Ponds (Minnesota) says the "investment ranges between $120-$220 a square foot" and sells tiers from $10,500 to $12,500 up to $26,000 to $36,000. Black Koi Water Features (western North Carolina) prices an ecosystem koi pond at $16,000 to $19,000 for 7 by 10 feet, $33,000 to $40,000 for 10 by 15 feet and $70,000 to $85,000 for a custom 21 by 26 feet. Premier Ponds (Glenwood, Maryland) starts a small 8 by 10 foot koi pond at $14,995. Midwest Pond Features (Glen Ellyn, Illinois) prices a 1,500 to 3,000 gallon pond at $15,000 to $30,000 and names "Size, depth, rock, and filtration" as "the biggest cost drivers" with labor "Usually 30 to 50 percent of the total." Tussey Landscaping (Hollidaysburg, Pennsylvania) is the low outlier at $6,000 to $9,000 for a 500 to 1,000 gallon koi pond, and it accepts a "Minimum depth: 2 feet" where Midwest requires "a minimum of around 3 feet".

Owners on the koi forums price by the gallon. A Koi-Bito poster asking about koi pond contractors reported a 20 by 10 by 3 foot pond of about 4,500 gallons with a waterfall quoted at $37,709.90, which works out to $8.38 per gallon. A Koiphen thread on building a 3,500 gallon koi pond puts the rule at $2 per gallon doing the work yourself and $5 per gallon professionally built. Neither forum page would load for this article, so both figures come from search snippets and the poster handles could not be confirmed.

Per square foot and per gallon, side by side

Unit prices as published or as computed from the source's own rows. Gallons use length times width times depth times 7.48. Computed figures are marked.
Source	Basis	Per square foot	Per gallon
HomeGuide (snippet)	general pond, excavation scale	$2.50 to $9.00	not given
Angi koi pond (snippet)	tiers at 3, 3.5 and 4 feet deep	$14 to $50 stated; $40 to $125 computed from its tiers	$1.34 to $5.57 computed
Bob Vila	small to medium ponds	$40 to $60	not given
Fixr capacity table	1,300 to 10,000 gallons (its footprints at 2 feet)	$52 to $182 computed	$3.50 to $12.31 computed
LawnLove koi pond	recommends 3 to 4 feet deep	$50 to $130	$1.67 to $5.79 computed at 3 to 4 feet
HomeAdvisor koi pond	"ideal depth" 3 to 4 feet	$75 to $125	not given
Superior Ponds, Minnesota	benchmark	$120 to $220	not given
Premier Ponds, Maryland	8 by 10 to 25 by 25 feet	$141 to $187 computed	not given
Black Koi, North Carolina	7 by 10 to 21 by 26 feet	$128 to $271 computed	not given
Tussey and Midwest Pond Features	500 to 3,000 gallon koi ponds	not given	$5 to $20 computed
Koi-Bito and Koiphen posters	owner quotes	not given	$8.38 quoted; $2 DIY, $5 professional

Why the numbers disagree

Fixr's gallon table is its footprint table filled to two feet: 8 by 11 by 2 feet, times 7.48, is 1,316 gallons, which Fixr rounds to 1,300, and 26 by 26 by 2 is 10,113, which it rounds to 10,000. That matches the Aquascape kit depth of two feet. The koi pages assume 3 to 4 feet. Doubling the depth of an 8 by 11 foot pond from 2 to 4 feet takes the water from 1,316 to 2,633 gallons and the spoil from about 6.5 to about 13 cubic yards. With a 12 inch overhang buried at each edge, the liner at 2 feet deep is 14 by 17 feet, or 238 square feet; at 4 feet it is 18 by 21 feet, or 378 square feet, 59 percent more liner and underlayment for the same surface. Deeper walls need more and larger boulders to hold them (the 1-2-1 rock rule scales with wall height), and koi builders add UV, bottom drains and larger biological filtration that an ecosystem kit leaves out. Superior's $120 to $220 per square foot describes this deeper, heavier build; HomeGuide's $2.50 per square foot describes something else entirely.

Two figures circulate without a basis the reader can check. Angi's "$14 and $50 per square foot" does not match its own tiers, which work out to $40 to $125. The averages near $3,350 at HomeAdvisor and Bob Vila sit at the bottom of the installed ranges those sites print, which suggests they include small preformed ponds and partly DIY jobs, though neither site says how the average was built. At the small end, a 1,000 gallon pond is a 6 by 8 foot pond 3 feet deep or an 8 by 11 foot pond 2 feet deep, and the professional rows for that size run from $3,000 to $16,000. At 20,000 gallons no cost guide has a row at all; Black Koi's 21 by 26 at $70,000 to $85,000 and Premier's custom tier that "starts at $88,000" are the only published anchors.

What to do

Decide the depth before the footprint. Two feet is the depth of the Aquascape ecosystem kit, and 3 feet is the minimum for every koi builder except Tussey. That choice moves the price more than adding a foot of length.
Get your gallons and liner size from your own yard, then judge quotes per gallon against the owner reports above (about $5 a gallon for a plain professional build, $8 and up for a deep koi pond with a waterfall).
Price the kit separately. At 8 by 11 the Aquascape kit is $2,733.60 and The Pond Guy sells the DIY version for $1,519.99 (listing), so a $12,000 quote is about three quarters rock, excavation and labor. Ask for those as line items.
Do not compare a 2 foot ecosystem quote with a 4 foot koi quote on square footage. Compare them on gallons and liner square feet.
Do not use the HomeAdvisor or Bob Vila headline averages to judge a quote for a finished ecosystem or koi pond. They sit at the bottom of the installed ranges those sites print.

Contractors building the quote will find the takeoff method in how to estimate and quote a pond build, and our kits page lists the standard footprints with the parts in each.

The PondTools calculators for this

Start with the PondTools volume calculator (also standalone). It takes length, width and average depth in feet plus a shape setting (rectangular, circular or oval, or irregular) and returns gallons, so you can run the same footprint at 2 feet and at 4 feet. Then use the PondTools liner calculator (standalone), which takes the longest span, the widest span at right angles to it, the maximum depth, the overhang buried at each edge and a fold allowance, and gives the sheet size and liner square footage that the quotes are really charging for. If the pond has shelves, size the liner from the maximum depth. Tracing the yard in the PondTools app from a satellite or drone photo gives the real footprint, gallons and liner size before anyone quotes, and fills both calculators from the trace.