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Costco Grafton Gas Prices – Port Washington Rd

Regular · today
$4.479▼ −$0.020
Premium · today
$5.499

USD per gallon · Last updated October 31, 2026 · This station does not sell diesel

950 Port Washington Rd, Grafton, WI 53024-9201 · Open in Maps ↗

30-day range

where today sits
  • Regular$4.479 today · avg $4.250
    $4.099 low$4.679 high
  • Premium$5.499 today · avg $5.282
    $5.099 low$5.699 high

Price history at Grafton

Last 30 days · USD per gallon
RegularPremium

Regular: $4.199 on Oct 2 to $4.479 on Oct 31, low $4.099, high $4.679. Premium: $5.299 on Oct 2 to $5.499 on Oct 31, low $5.099, high $5.699.

Last updated October 31, 2026. Prices are collected once daily and can lag same-day changes at the pump.

Today’s price in context

At $4.479 for Regular, Grafton is the most expensive of 12 Costco gas stations in Wisconsin today, $0.414 above the Wisconsin average of $4.065.

Menomonee Falls, 13.6 mi away, is $0.480 cheaper.

vs the US average
$0.204 above, at $4.275
Premium over Regular
$1.020 — the Wisconsin median is $0.950
Regular over the last 30 days
up $0.280
Days the price changed
10 of 30 reported days
Latest day at the 30-day low
October 23, 2026, at $4.099
15-gallon fill
$67.19, $5.70 more than at the 30-day low
Nearest cheaper station
Menomonee Falls — 13.6 mi

Grafton is located at 950 Port Washington Rd, Grafton, WI 53024-9201, in Wisconsin. The gas station sits in the warehouse parking lot and is open to Costco members, selling Regular and Premium — this location does not sell diesel. Gas station hours are 6 a.m. – 10 p.m. on weekdays, 6 a.m. – 8:30 p.m. on Saturdays and 6 a.m. – 7:30 p.m. on Sundays, in local time.

Station details

Grafton Gas station hours

Mon–Fri
6 a.m. – 10 p.m.
Saturday
6 a.m. – 8:30 p.m.
Sunday
6 a.m. – 7:30 p.m.

Grafton Warehouse hours

Mon–Fri
10 a.m. – 8:30 p.m.
Saturday
9:30 a.m. – 7 p.m.
Sunday
10 a.m. – 6 p.m.

Costco gas near Grafton

  1. 1Menomonee FallsMenomonee Falls, WI · 13.6 mi$3.999Regular
  2. 2PewaukeePewaukee, WI · 22.5 mi$4.049Regular
  3. 3New BerlinNew Berlin, WI · 27.8 mi$4.099Regular
  4. 4OconomowocOconomowoc, WI · 32.0 mi$4.089Regular
  5. 5Pleasant PrairiePleasant Prairie, WI · 52.5 mi$3.999Regular

Distances are straight-line.

Cities near Grafton

At this location

Warehouse opened
August 2007
Warehouse phone
(262) 204-1050
Pumps open early
4 hours before the warehouse on weekdays

Also at this warehouse: a food court, a pharmacy, an optical department, a hearing aid center and a tire center.

Frequently asked questions

How much is gas at Costco Grafton today?

As of October 31, 2026: Regular $4.479 and Premium $5.499 per gallon. Prices are collected once a day, so the pump can differ.

What time does the Costco Grafton gas station open?

The pumps are open 6 a.m. – 10 p.m. weekdays, 6 a.m. – 8:30 p.m. Saturdays and 6 a.m. – 7:30 p.m. Sundays, in local time. The pumps open 4 hours before the warehouse on weekdays.

Does the Costco Grafton gas station sell diesel?

No — this station sells Regular and Premium, and has reported no diesel price in the last 30 days.

Is Costco Grafton cheaper than the average Costco station in Wisconsin?

No — at $4.479, Regular here is $0.414 above the average Costco price in Wisconsin, $4.065.

Where is the Costco Grafton gas station?

At 950 Port Washington Rd, Grafton, WI 53024-9201. It sits in the Costco warehouse parking lot and is open to members only.

Do you need a Costco membership to buy gas?

Yes — a Gold Star, Executive or Business membership card has to be scanned at the pump before it will dispense, though a Costco Shop Card also works for non-members.

What payment methods does the Costco gas station accept?

Visa, PIN debit and the Costco Shop Card; US Costco fuel pumps take no cash and no Mastercard, American Express or Discover.

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