Steel Storage Tanks for Water Treatment Facilities
MMI Tank designs, fabricates, and erects bolted and field-welded steel tanks for municipal and industrial water treatment plants across the western United States. From raw water intake reservoirs to finished water distribution storage, our tanks are engineered to meet AWWA, NFPA, and state regulatory requirements — and built to perform for decades in continuous service.
Whether you need a 50,000-gallon bolted ground storage tank for a rural water district or a 3,000,000-gallon field-welded reservoir for a regional treatment plant, MMI handles engineering, fabrication, coating, foundation, and erection under a single contract.
Water Treatment Tank Applications
Potable Water Storage
Ground-level welded and bolted reservoirs for treated drinking water. All interior coatings are NSF/ANSI 61 certified for potable water contact. Tanks are designed to AWWA D100 (welded) or AWWA D103 (bolted) with seismic analysis per ASCE 7. Capacities from 10,000 gallons to over 5,000,000 gallons.
Raw Water and Intake Storage
Pre-treatment holding tanks for surface water, groundwater, or blended sources. Carbon steel construction with corrosion-resistant coatings selected for your specific water chemistry — hardness, pH, dissolved solids, and chloride levels all influence coating specification.
Process and Equalization Tanks
Equalization basins, flocculation chambers, and chemical contact tanks sized for your plant’s flow rate and detention time requirements. Custom baffle and inlet/outlet nozzle configurations to optimize mixing and minimize short-circuiting.
Filter Backwash and Washwater Recovery
Holding tanks for filter backwash water, sized to your backwash frequency and volume. Designed with proper inlet diffusion and decant systems for settled solids return.
Chemical Storage
Bulk storage for treatment chemicals — sodium hypochlorite, ferric chloride, alum, polymer, caustic soda, and lime slurry. Material selection and coatings specified for each chemical’s concentration, temperature, and exposure duration.
Clearwell and Finished Water
Contact time (CT) tanks for disinfection compliance. Engineered with internal baffling to achieve required CT values for chlorine or ozone disinfection. Covered with aluminum dome or flat panel roofs to maintain water quality.
Fire Protection Water Storage
Dedicated NFPA 22-compliant fire water tanks, sized to your fire flow rate and duration. Available in bolted or welded construction with freeze protection options for cold-climate installations.
Codes and Standards
| Standard | Application |
|---|---|
| AWWA D100 | Welded steel tanks for water storage |
| AWWA D103 | Factory-coated bolted steel tanks for water storage |
| NFPA 22 | Water tanks for private fire protection |
| NSF/ANSI 61 | Drinking water system components — coating certification |
| ASCE 7 | Seismic and wind loading |
| API 650 | Non-potable water storage (industrial, process) |
| Ten States Standards | Recommended standards for water works (Great Lakes–Upper Mississippi) |
Bolted vs. Welded for Water Treatment
Both construction methods serve water treatment well. The decision depends on capacity, schedule, site access, and owner preference.
| Factor | Bolted (AWWA D103) | Welded (AWWA D100) |
|---|---|---|
| Installation speed | ✅ 2–4 weeks typical | 6–12 weeks typical |
| Factory coating quality | ✅ Climate-controlled bake oven | Field-applied after erection |
| Large diameter (>100 ft) | Available | ✅ Standard |
| Custom internal baffling | Limited | ✅ Unlimited flexibility |
| Future expansion/relocation | ✅ Disassembles | Permanent |
| Potable water approved | ✅ NSF 61 coatings | ✅ NSF 61 coatings |
MMI builds both. Our engineers will recommend the construction method that fits your project’s capacity, timeline, and budget — not the product line we happen to stock. Learn more about our bolted tanks → | Learn more about our field-erected welded tanks →
Coating Systems for Water Service
The coating system is what protects the steel from corrosion and maintains water quality throughout the tank’s service life. For water treatment, every interior coating must meet NSF/ANSI 61 certification. MMI’s coatings division applies all systems in-house:
- Glass-fused-to-steel (bolted tanks) — factory-fused ceramic coating bonded to the steel at 1,500°F+. The most corrosion-resistant option, with service life exceeding 40 years in many installations.
- Factory-baked epoxy (bolted tanks) — applied and cured in a controlled oven environment. Excellent uniformity and adhesion.
- Field-applied epoxy (welded tanks) — high-build epoxy systems applied after abrasive blasting. SSPC SP-10 near-white metal surface preparation standard.
- Polyurea — fast-cure option for rehabilitation and relining of existing tanks.
- Zinc-rich primer + epoxy topcoat — exterior protection for atmospheric corrosion.
MMI’s Water Treatment Experience
Our water treatment tank portfolio includes projects for:
- Municipal water utilities and special districts
- Private community water systems
- Industrial facilities requiring process and cooling water storage
- Military installations and federal facilities
- Rural water districts and tribal water systems
We hold contractor licenses in Arizona, California, Colorado, Nevada, New Mexico, Oregon, Washington, Wyoming, Hawaii, Alaska, and South Dakota and routinely mobilize crews to remote and challenging sites throughout the region.
Water Treatment Tank FAQ
What size water treatment tanks does MMI build?
From 10,000 gallons for small community systems up to 5,000,000+ gallons for regional reservoirs. Both bolted and welded construction are available across the full capacity range.
Are MMI tank coatings safe for drinking water?
Yes. All interior coatings for potable water service are NSF/ANSI 61 certified. We provide coating certifications and material safety data as part of our project documentation.
Can MMI handle the foundation for a water storage tank?
Yes. Our foundations team designs and constructs concrete ringwall and slab foundations, keeping the tank and foundation under a single contract.
Does MMI perform tank inspections and repairs?
Yes. Our National Board R stamp and API 653 program cover inspection, repair, relining, and reconstruction of existing water storage tanks.
How do I get a quote for a water treatment tank?
Call (602) 272-6000, email info@mmitank.com, or request a quote online. Provide your target capacity, stored product, site location, and governing code if known — our engineers will handle the rest.
Request a Water Treatment Tank Quote
📞 (602) 272-6000 · 📧 info@mmitank.com · Request a quote online →
