Water tank projects have high needs for performance, compliance, and longevity due to a number of factors, from water safety regulations to weather and environmental stress. This article touches on the eight elements of most water tank painting projects. Whether you’re in charge of tanks that are part of a municipal water system or installed for commercial / industrial use, we hope you find this a helpful checklist of reminders and considerations.

1) Safety First

Most tank cleaning and coating projects are not DIY projects; they're simply too risky, not to mention the technical skills required. Painters USA always keeps safety and risk management a top priority. Just one look at the image above, from one of our water tank projects, and you can understand why.

We thoroughly train and prepare our crews for aerial lift operations, working in confined spaces, and other safety topics. We also monitor site safety to ensure your employees and any other contractors at the project location are safe. Our commitment to safety is backed by our ISN RAVS Plus® verified HSE status.

2) Tank Condition

Painters USA will begin with a thorough assessment of the current condition of the tank(s), supported by:

• Decades of experience working with steel and concrete tanks.
• Deep coating knowledge, validated through our NACE / AMPP coating certifications.
• Input from and relationships with leading manufacturers of coatings for marine and water applications.

Unless it’s a brand new tank, your own assessment based on your operational knowledge is important. Whatever operational and maintenance data you can share is also very helpful to give us a 360-degree understanding of your needs and situation.

3) Surface Preparation

Without proper surface prep, a water tank coating project is doomed to fail, especially external tanks and towers, which are subject to the relentless forces of weather and the environment–UV exposure, wind, rain, snow, ice, blowing dirt and debris. Rust is a routine problem, not to mention cleaning away other contaminants, which will vary depending on location and surrounding area.

If blast cleaning is required, our specifications will be very detailed, including the blasting medium, particle size, recommended surface profile and degree of cleanliness required, whether to white (completely cleaned) or near white (surface may contain some staining, but not more than 5% of each unit area) standards.

4) Suitable Coatings

It’s important for tanks that store potable water to comply with ANSI/NSF Standard 61 for Drinking Water System Components, which most US states and Canadian provinces either require or recommend. Standard 61 covers various elements of water treatment and distribution systems, including protective barrier materials like paints and coatings.

The American Water Works Association D102 standard for coating steel water-storage tanks is another important standard for coating / recoating interior and exterior surfaces of steel tanks used for potable water storage in water supply service.

It used to be that above-ground, in-service water storage tanks had to be drained before coating or painting, as coatings back then would often fail due to condensation. That requirement changed with the advent of moisture-cured, surface-tolerant coating technology.

Coating adherence and performance are always top priorities. That’s why we partner with and recommend coatings from leading manufacturers like Sherwin-Williams and PPG. Having options allows us to come up with the perfect formulation for any unique needs or circumstances.

5) Coating Application

Exterior surfaces of water storage tanks are generally coated with a three coat zinc-epoxy-polyurethane system with a minimum dry film thickness, curing time and window between each coat as specified by the coating manufacturer.

Interior wet surfaces (exposed to stored water or its vapor) are generally coated with a three-coat zinc-epoxy-epoxy system with a minimum dry film thickness, NSF Standard 61-approved for potable water.

However, the best coatings on the market will not perform well over time with improper or inexperienced application, plus it could void the coating manufacturer warranty.

6) Finishing Work

Sealers and finishing coats, including the painting of a company logo or the name of the municipality, are often part of a water tank painting project. It’s best to work with a painting contractor who understands these products, and if a logo or text is part of the project scope, to find a contractor with proven experience working with templates, branding guidelines, and color specifications to ensure the results meet your expectations.

7) Waste Management

Cleaning and coating water tanks can be a messy process. That's why it’s important for the contractor to contain (as much as possible) all debris and other contaminants, with protection of adjacent areas and consideration for neighboring properties beyond the site location property limits.

With Painters USA, you can also rest assured that all waste materials will be disposed of in accordance with local, state, and federal guidelines. Anything defined as hazardous or toxic waste will be placed in designated containers, and no paints or solvents will ever be disposed of by pouring them on the ground. Our motto is to leave no trace behind.

8) Timing and Season

Most water tank projects continue to be done during the summer months. Moisture-cured urethane coatings can be applied almost any time of the year, except during very cold temperatures, when dew or condensation could freeze on tank surfaces.

Another seasonal consideration is extreme heat, which is becoming a bigger factor all across the country. We can recommend coating systems to help keep tanks cool. And note that we closely monitor the safety and welfare of our crews as the temperature rises during the hottest days of summer projects.

Of course, the best timing is timing that meets your needs. Tell us your deadlines and operating schedules and we’ll deliver on time.

Recommended water tank painting contractor checklist

The minimum requirements we suggest you look for when selecting a painting contractor for your water storage tank project:

Steel tank cleaning and coating experience to be prepared for anything.

Technical coating expertise for conditions, mil thickness, performance, and compliance.

Regulatory awareness and understanding to ensure compliance.

Exemplary safety record and adequate insurance for risk management.

Ability to meet deadlines and minimize downtime.

It should go without saying that Painters USA checks all of the above requirements, and we’re happy to discuss your water storage tank needs.