When you watch out for bolted water tank quotation hidden cost while sourcing bolted sectional stainless steel or FRP moulded tank panels, it’s easy to fix your attention only on panel thickness, material grade and total tank capacity. We hear this complaint often from contractors and overseas buyers: the initial price looks competitive, but extra accessory fees pop up later.

We supply moulded tank panels only. Our scope does not cover on-site assembly, field welding or hydrostatic pressure testing. This checklist helps you draw clear boundaries with any tank supplier before signing off your proforma invoice. It works for 304 / 316 stainless steel modular tanks and FRP bolted panel tanks.

Sealing Gaskets

EPDM or food-grade silicone gaskets seal every joint between panels. Many low quotations list panels alone, with gaskets sold as a separate line item. Without matching gaskets, leakage is almost guaranteed once the tank is put together.

Double-check three points: gasket material grade, whether all panel seams get gaskets, and whether spare gaskets are packed with your shipment.

Internal link: Bolted Sectional Water Tank Gasket Selection: EPDM, Silicone & Rubber Guide

Stainless Steel Bolts, Nuts & Washers

Fasteners hold the whole tank structure together. Cheap bare-panel offers frequently exclude bolts, nuts and lock washers.

For potable water storage, confirm the bolt grade: A2-70 for general fresh water, A4-70 for coastal, salt-laden environments. Match bolt quantity to your panel layout drawing.

Internal link: Common Buying Pitfalls for Stainless Steel Fasteners & Bolts of Modular Water Tanks

Openings and Flanges (The #1 Hidden Cost Trap)

This is the spot that trips most buyers up. Some factories ship blank panels only. Cutting openings, welding flanges and machining all become separate charges.

Before quoting, list all required ports and confirm they are included:

• Inlet flange
• Outlet flange
• Overflow flange
• Bottom drain / blowdown flange
• Vent flange

Agree on flange standard up front: ANSI, DIN or GB, plus exact size for each connection.

Manhole Assembly

You need a manhole for periodic inspection and tank cleaning. Do not assume it comes as standard.

Ask if the quotation includes the cover, hinge, locking mechanism and integrated sealing ring. Some suppliers treat manholes as an optional upgrade.

Internal link: Step-by-Step Guide to Cleaning & Disinfecting Drinking Water Storage Tanks

Internal Support Bracing

Larger sectional tanks need internal stainless bracing to resist hydrostatic load. Several suppliers separate this support frame from the panel package and price it individually.

Confirm if bracing is included, plus the material grade of the support structure.

What Is Usually Excluded From Our Panel-Only Quotation

Clarify these items early to avoid misalignment with your project team:

• On-site installation labour
• Field welding work
• On-site hydrostatic pressure test
• External valves and pipework
• Concrete foundation and civil works
• External insulation or cladding (only included with special written agreement)
• Delivery to site: our standard quote covers loading at factory; sea freight and local inland transport are separate

Quick PI Clause You Can Copy

Add this simple sentence to your proforma invoice to lock the scope:

Price includes moulded tank panels, full set of gaskets, bolts & washers, required flanges, manhole assembly and internal bracing per approved drawing. No extra accessory charges apply.

These small scope gaps add up quickly. A clearly defined quotation keeps your project budget predictable and avoids shipment delays.

FAQ

Q: Does every bolted tank quotation automatically include gaskets? A: No. Many suppliers quote bare panels only. Always verify gasket inclusion and material grade before placing an order.

Q: Is hydrostatic water test included in moulded panel pricing? A: For our supply scope, no. We only manufacture and ship tank moulded panels and matching accessories. On-site pressure testing belongs to the installer or local contractor.

Q: Can I add extra flanges after production starts? A: It is possible, but it usually carries extra machining cost and delays your shipment. Finalise all opening sizes and locations before production.