BDF Underground 20000L Water Tank

A 20 m³ BDF water tank under the yard

The BDF water tank from LVJIA is a bolted, buried storage tank pressed from bimetallic composite plate at our own plant in Dezhou, Shandong. It holds 20 cubic metres — 20,000 litres — entirely below ground, so the car park, lawn or loading yard above it stays in use.

What is a BDF water tank?

A BDF water tank is a sectional tank assembled below ground from 1000 × 1000 mm pressed panels. Each panel is drawn in a single press stroke from a composite plate: a food-grade stainless layer on the face that meets the water, hot-dip galvanised steel behind it to carry the load. The panels bolt together inside the excavation, so no welding happens on site and no welded seam is ever in contact with the stored water. LVJIA builds this tank from 1 to 1,000+ m³, which means the volume follows the pit you have dug rather than a fixed catalogue size.

Why a 20 m³ BDF water tank is the common first size

Twenty cubic metres is the volume most sites land on: enough to carry a small building through a day of mains failure, enough to meet a modest sprinkler demand, and small enough that the excavation is a day of machine work rather than a civil-engineering project. At 2 m deep the footprint is about 5 × 2 m, which fits beside a driveway or under a visitor parking bay. The same tank can also be laid out as 4 × 2.5 × 2 m, 5 × 4 × 1 m or 10 × 2 × 1 m, so the shape follows the space rather than the other way round.

How the BDF water tank is built

Three things separate this BDF water tank from a coated steel tank. First, there is no coating: the corrosion-resistant surface is the stainless face of the panel itself, so there is nothing to blister, peel or repaint. Second, the panel is drawn rather than fabricated, so the water never touches a heat-affected zone where pitting normally starts. Third, every joint is closed with EPDM strip and stainless fasteners outside the water path, which means a single panel can be replaced years later without cutting the tank open. The module is reinforced on all four corners, and the wall is carried on a 16 mm section rated for a full 4.5 m of head.

Technical data for the BDF water tank

Sizes, panels and capacity

Because the module is a 1 m panel, capacity steps in whole cubic metres and nothing is wasted on a bespoke mould. A 20 m³ tank is 20 panels of floor area and as many courses as the depth needs. Deeper tanks take thicker panels on the lower courses, which is where the 2 mm to 5 mm range comes in, and the roof takes a sealed, vented manhole of 600 × 600 mm.

Testing, standards and certification

Every BDF water tank is filled and held at full head for 48 hours before it leaves the factory, and no joint is allowed to weep. The composite plate carries drinking-water contact report SP2630499 from the Dezhou Institute of Product Quality Standards and Metrology, and the plant holds ISO 9001 with CE marking on the product. Copies of the report and the certificate ship with the order, and you can see the full set on our certifications page. The same specification is published on our Made-in-China storefront, where LVJIA is an audited supplier.

Where the BDF water tank is used

• Residential blocks — day storage under the visitor parking, feeding a basement booster set.
• Small industrial plants — process make-up water below the yard, out of the sun and clear of forklift traffic.
• Fire reserve — a dedicated buried volume that day-to-day use cannot draw down.
• Farms and rural supply — a buffer between a borehole and demand, with no evaporation loss.

How to order a BDF water tank

Pricing for the BDF water tank starts at US$200 per cubic metre, falling to US$180 from 10 m³ and US$150 from 50 m³, FOB Tianjin or Qingdao. The minimum order is one set. Samples ship in 3 to 5 days and batch orders in 15 to 25 days from Dezhou, Shandong, on wooden pallets. LVJIA has been an audited supplier on Made-in-China since 2025 and holds a 5.0 store rating on Alibaba with 100% on-time dispatch, a response time under an hour and a 25% reorder rate. Annual capacity at the Dezhou plant is 60,000 tonnes.

Send the pit dimensions and the volume you need and LVJIA returns an arrangement drawing and a panel schedule before you commit to anything. If you would rather talk it through first, our engineers answer specification questions directly through technical help, and the rest of the range sits on the BDF underground water tank page.

Other LVJIA tanks worth comparing

If the material has to change, the SMC water tank for hotels is the same tank in moulded GRP, for sites where no metal may touch the water, while the sealed galvanized water tank builds it in hot-dip galvanized steel. Elsewhere in the BDF underground range there is the BDF fire water tank for fire reserves and the food grade BDF tank for drinking water.

1–1,000+ m³

Built to order

15–25 d

Batch lead time

0–100 °C

Water temperature

• Bimetallic panel. — A food-grade stainless face to the water, hot-dip galvanised steel behind it for strength — pressed in one stroke, not laminated.
• Nothing welded wets. — Panels are drawn, not fabricated, so the water never touches a heat-affected zone where corrosion starts.
• Bolted and gasketed. — EPDM strips and stainless fasteners close every joint, so a panel can be replaced without cutting the tank open.