What Is a Frac Tank?
A frac tank is a large portable steel storage tank mounted on a semi-trailer chassis, designed to be hauled to a job site, set in place, and used as temporary liquid storage. The standard size holds 500 barrels — approximately 21,000 gallons. They're built from carbon steel, open or closed top depending on the application, and equipped with valves, manways, vents, and sight gauges.
The name comes from hydraulic fracturing ("fracking") operations in the oil and gas industry, where banks of these tanks were used to store frac fluid on-site. But the term has long outgrown that original use — today you'll find frac tanks on construction sites, at refineries during turnarounds, at municipal water plants, at power generation facilities, and anywhere a large volume of liquid needs to be stored temporarily without a permanent tank infrastructure.
The key advantage is simple: a frac tank goes wherever a semi-truck can go, sets up in an hour, and holds the equivalent of a small swimming pool. When the job is done, you call the rental company and they haul it away. No concrete, no engineering, no permits in most cases.
Frac Tank Sizes and Specifications
| Size | Capacity (BBL) | Capacity (Gallons) | Length | Width | Height | Empty Weight |
|---|---|---|---|---|---|---|
| Mini Frac Tank | 130–210 bbl | 5,500–8,800 gal | 20–30 ft | 8 ft | 6–7 ft | ~15,000 lbs |
| Standard (most common) | 500 bbl | 21,000 gal | ~48 ft | ~8 ft | ~7.5 ft | ~40,000 lbs |
| Large | 750 bbl | 31,500 gal | ~53 ft | ~8.5 ft | ~8 ft | ~50,000 lbs |
| Dimensions vary by manufacturer. Dragon, Southern Frac, and other manufacturers each have slightly different specs. Always confirm exact dimensions with your rental supplier before delivery. | ||||||
Real-World Uses: What Frac Tanks Are Actually Used For
Most content about frac tanks focuses on oil and gas. But the majority of frac tank rental demand today comes from other industries. Here's where they actually show up and why:
Refinery and Industrial Plant Turnarounds
When a process vessel — a reactor, a column, a storage drum — needs to be taken offline for inspection or maintenance, it has to be drained. That liquid can't always go straight to the wastewater plant. Process water from vessels often contains hydrocarbons, elevated BOD, suspended solids, or chemical residues that would shock or overwhelm a biological treatment system if sent all at once.
The solution is a frac tank staged between the vessel drain and the wastewater plant. The vessel drains into the frac tank, and the frac tank feeds the wastewater system slowly — controlled flow, controlled loading rate. The biological process in the treatment plant never sees a hydraulic or organic shock. This is flow equalization at its most basic, and it's one of the most common uses of frac tanks at refineries and chemical plants during shutdowns.
Wastewater Treatment Flow Equalization
Package treatment plants — the prefabricated activated sludge or extended aeration systems used at remote industrial sites, construction camps, and small municipalities — are particularly vulnerable to flow variation. A plant designed for 50,000 GPD that receives 150,000 GPD for four hours and then nothing for the rest of the day will perform poorly. Biological processes need stable hydraulic and organic loading to function.
Frac tanks serve as equalization basins ahead of the treatment unit. Influent flows into the frac tank, and a pump or gravity feed controls the flow into the plant at a steady, manageable rate. For remote or temporary installations where building a concrete equalization basin isn't practical, a rented frac tank is the engineered solution.
Remote Industrial Utility Water Storage
At remote power generation facilities, compressor stations, pipeline terminals, and construction camps, utility water — wash-down water, equipment cooling, fire suppression supply, process water — is often not available from a municipal source. The site has to create its own supply.
A common setup: pull raw water from a nearby surface source, treat it through media filtration and possibly UV or chemical disinfection, and store the treated water in one or more frac tanks for use as utility water. The frac tanks serve as the treated water reservoir for the life of the project — which in a long-term industrial setting can mean years, not weeks. The rental continues as long as the facility operates.
Emergency Municipal Water Supply
When a water main breaks, a well fails, a treatment plant goes offline, or a contamination event affects a municipal supply, utilities need large-volume portable water storage immediately. Frac tanks can be deployed within hours and serve as temporary distribution points or storage buffers while permanent infrastructure is repaired.
Construction Dewatering and Site Water
Large construction sites use frac tanks for concrete washout water, stormwater containment, dewatering holding, and dust suppression water supply. A site excavating below the water table will pump groundwater continuously — that water has to go somewhere while it's being tested and routed to proper discharge.
Agricultural Applications
Frac tanks show up on large farming operations for liquid fertilizer storage, irrigation water staging, and livestock water supply in remote areas where a permanent tank isn't justified for a seasonal operation.
Frac Tank Dimensions: Detailed Breakdown
Dimensions matter most at two points: delivery access and site placement. Here are the critical measurements for a standard 500 bbl frac tank:
| Measurement | Standard 500 BBL | Mini Frac Tank | Notes |
|---|---|---|---|
| Overall length | ~48 ft | ~20–30 ft | Includes trailer tongue |
| Tank length | ~40 ft | ~18–22 ft | Shell only |
| Width (exterior) | ~8 ft 6 in | ~8 ft | Standard legal trailer width |
| Height (transport) | ~13–14 ft | ~11–12 ft | Tank on trailer chassis |
| Height (tank shell) | ~7 ft 6 in | ~6–7 ft | Shell height only |
| Ground clearance | ~18–24 in | ~16–20 in | Bottom of tank to ground |
| Manway diameter | ~18–24 in | ~18 in | Access port on top |
| Inlet/outlet size | 3–4 in (typical) | 3 in (typical) | Varies by configuration |
| Confirm exact dimensions with your rental supplier before delivery. Dragon, Rain for Rent, Southern Frac, and other manufacturers vary. Always measure your access path and overhead clearances. | |||
Overhead Clearance
The most commonly overlooked dimension. A frac tank on its trailer stands 13–14 feet tall. Before delivery, walk your access route and note every overhead obstacle: power lines, pipe racks, building overhangs, tree limbs, gate frames, and bridge clearances. A standard utility power line often runs at 15–18 feet but can sag lower — call your utility if you're unsure. A frac tank delivery truck that clips a power line shuts down your site and creates a serious liability situation.
Access Road Width and Turn Radius
Delivery requires a semi-truck with a 48-foot trailer. You need a clear path at least 14 feet wide with no sharp turns tighter than a standard truck can negotiate (approximately 45-foot outside turn radius). If your site access involves a tight gate or a 90-degree turn from a narrow road, discuss this with your supplier before booking — some sites require a crane to spot the tank rather than a direct delivery, which adds cost.
Frac Tank Rental: What You Need to Know
Before calling a rental supplier, work through our frac tank specification guide — it walks through every decision point from liquid compatibility to secondary containment requirements so you can give your supplier exactly what they need on the first call.
Typical Rental Costs
| Duration | Monthly Rate | Notes |
|---|---|---|
| Short-term (1–4 weeks) | $800–$1,500/mo | Minimum charges often apply; mobilization adds $500–$2,000+ |
| Standard (1–6 months) | $600–$1,000/mo | Most common rate range for industrial projects |
| Long-term (6+ months) | $400–$700/mo | Negotiable; life-of-project contracts often get significant discounts |
| Rates vary significantly by region, supplier, and market conditions. Permian Basin and Gulf Coast markets run higher due to demand. Always get 3 quotes. | ||
What's Included (and What's Not)
A standard frac tank rental includes the tank, delivery to site, and pickup at end of rental. It does not typically include:
- Secondary containment berms — required by many environmental regulations when storing hydrocarbons or chemicals. Budget $200–$600/mo extra for a containment berm.
- Manifold and hose connections — pumps, hoses, and manifold piping for filling and discharging are usually the customer's responsibility or rented separately.
- Cleaning before return — if you've stored anything other than clean water, expect a cleaning charge. Hydrocarbon-contaminated tanks run $1,500–$5,000+ to clean.
- Permits — some jurisdictions require permits for temporary storage of certain liquids. This is your responsibility.
Site Requirements
- Access: Delivery requires a semi-truck and trailer. A clear, level access path at least 14 feet wide and able to support a loaded truck.
- Level pad: The tank needs to sit on a reasonably level surface. A 2–3% grade maximum is typical. Unlevel placement stresses the chassis and affects accurate volume readings from gauge sticks and sight glasses.
- Ground bearing: Full tank weight (175,000–200,000 lbs) distributed over the trailer footprint. Soft or wet ground, underground utilities, and unprepared surfaces are common problems. Discuss with your supplier and consider crane mats or gravel pads for soft sites.
- Overhead clearance: The tank stands approximately 13–14 feet high on its trailer. Watch for overhead power lines, pipes, and structures.
Major Frac Tank Rental Companies
These national and regional suppliers cover most of the US market. Rates and availability vary by location — always call your local branch for current pricing:
- Rain for Rent — large national network, well-stocked, strong service infrastructure. One of the most commonly used suppliers for industrial applications.
- United Rentals — the largest equipment rental company in North America; frac tanks available through their fluid solutions division.
- Adler Tank Rentals — specialty liquid containment and tank rental, particularly strong in the Northeast and Mid-Atlantic.
- Sunbelt Rentals — broad national coverage, competitive pricing, good for construction and municipal applications.
- Dragon Products / Dragon Tank — a major frac tank manufacturer that also operates a rental fleet, particularly strong in oil and gas regions.
- Regional suppliers — in Permian Basin, Gulf Coast, and other oil field markets, regional suppliers often have better availability and lower prices than nationals. Search "frac tank rental [your city]" and call 3–4 suppliers.
Frac Tank Strapping Chart: Measuring Volume
A strapping chart (also called a strap chart or volume chart) converts a physical measurement — usually a gauge stick reading in inches or fractions — to a volume in barrels or gallons. Every frac tank should have a strapping chart affixed to the tank or available from the supplier.
The standard 500 bbl frac tank has a maximum gauge reading of approximately 90–96 inches depending on manufacturer. Here's a representative table for a Dragon 500 bbl tank — always verify against your specific unit's chart:
| Inches | Barrels | Gallons |
|---|---|---|
| 12 | 63 | 2,646 |
| 24 | 130 | 5,460 |
| 36 | 198 | 8,316 |
| 48 | 268 | 11,256 |
| 60 | 338 | 14,196 |
| 72 | 405 | 17,010 |
| 84 | 464 | 19,488 |
| 90 | 490 | 20,580 |
| 96 (full) | 500 | 21,000 |
| Representative values only. Always use the chart attached to your specific tank — manufacturer and model variations are significant. | ||
Frac Tank vs. Other Options
| Frac Tank | IBC Tote (275 gal) | Poly Storage Tank | Baker Tank | |
|---|---|---|---|---|
| Capacity | 21,000 gal | 275 gal | 50–20,000 gal | 10,000–21,000 gal |
| Portable | ✅ Trailer-mounted | ✅ Forklift/pallet | ❌ Stationary | ✅ Trailer-mounted |
| Rental available | ✅ Widely | ✅ Common | ❌ Rare | ✅ Specialty |
| Setup time | 1–2 hours | Minutes | Hours to days | 2–4 hours |
| Best for | Large-volume industrial, flow eq. | Small batch, chemical feed | Permanent storage | Wastewater, industrial |
| Cost range | $500–$1,500/mo rental | $75–$150/mo rental | $500–$20,000 purchase | $800–$2,000/mo rental |
Frequently Asked Questions
"Frac" is short for hydraulic fracturing — the oil and gas well stimulation process that uses high-pressure fluid injection to crack rock formations. Frac tanks were originally developed to store the large volumes of water and frac fluid needed at well sites. The name stuck even as the tanks became standard equipment across virtually every industrial sector. You'll sometimes see it spelled "frack tank" but "frac tank" is the industry-standard spelling.
Yes — a frac tank is a permit-required confined space under OSHA 1910.146. Entry for inspection, cleaning, or maintenance requires a confined space entry permit, atmospheric testing (oxygen, LEL, toxic gases), and a trained attendant outside the tank at all times. Never enter a frac tank without following your facility's confined space entry procedure. This is non-negotiable regardless of what the tank has held.
Start with the national suppliers — Rain for Rent, United Rentals (Fluid Solutions division), Sunbelt Rentals, and Adler Tank Rentals all have broad national coverage. Call your local branch rather than using online inquiry forms — you'll get faster response and can negotiate pricing directly. In oil field regions (Permian, Bakken, Eagle Ford, Gulf Coast), regional suppliers often have better availability and more competitive rates than the nationals. Search "frac tank rental [your city or state]" and call at least 3 suppliers. Get quotes that include mobilization, demobilization, and any environmental compliance requirements for your site.
A standard 500 bbl frac tank weighs approximately 38,000–45,000 lbs empty depending on manufacturer and configuration. When full of water (8.34 lbs/gallon × 21,000 gallons = 175,140 lbs of water), total weight approaches 215,000–220,000 lbs. This exceeds legal road weight limits, so frac tanks are transported empty. Site soil bearing capacity, road access, and pad preparation must account for the full loaded weight.
Standard carbon steel frac tanks are not rated or certified for potable water. They're used for process water, utility water, wastewater, and non-potable industrial applications. If you need potable water storage in a frac tank configuration, there are specifically lined and certified tanks available — ask your rental supplier about potable water rated units. For emergency municipal water supply situations, the tanks must be properly cleaned, inspected, and certified before use, with appropriate documentation for your state health department.
Baker tanks are a brand of open-top welded steel portable storage tank, also trailer-mounted, typically used for wastewater, contaminated water, and industrial liquid holding. They're similar in concept to frac tanks but typically open-top (no manway cover on the top surface), making them better suited for applications where you're pumping or scooping material in from the top. Frac tanks are closed-top with manway access ports. In practice, the terms are sometimes used interchangeably in the industry, but they're technically distinct product categories. Your rental supplier can recommend the right type for your specific application.
There's no standard maximum rental period — frac tanks can be rented for as short as a week or as long as the project requires. Life-of-project rentals lasting 5–10 years are common at long-term industrial sites. Longer rental terms typically negotiate lower monthly rates. Most suppliers will want a written rental agreement for anything over 6 months. Make sure your contract addresses who's responsible for periodic inspection, maintenance of valves and seals, and what happens if the tank requires repair during the rental period.