When I get the tank what should I do first?
Sanitize each tank prior to use to remove any debris from the manufacturing process. When tanks are manufactured they do not have the holes for the fittings so holes are drilled and fittings installed, the tanks will have shavings from drilling the holes. We do not flush the tanks due to wanting tanks to be completely new and unused.

Tanks are made in a warehouse so maybe dusty or scuffed, this does not effect the use or safety of the tank, wipe with a damp cloth to remove surface dust or scuffs.

1. Prepare a chlorine solution using one gallon of water and a ¼ cup of household bleach (5% sodium hypochlorite solution)


Never mix bleach with ammonia or other cleaners.
Open windows and doors to get fresh air when you use bleach.

With tank empty, pour chlorine solution into tank. Use one gallon of solution for each 15 gallons of tank capacity.
2. Complete filling of tank with fresh water.
3. Allow to stand for three (3) hours
4. Drain and flush with potable fresh water.
Any residual chlorine odor will dissipate naturally.

Using chemical tablets to disinfect water
If you don’t have safe bottled water, water treatment tablets can be used to disinfect water. These tablets are popular among campers and hikers, as well as in other countries. They are available in different sizes and made to treat specific amounts of water.

Follow the manufacturer’s instructions on the label or in the package.
Chlorine dioxide tablets can kill germs, including Cryptosporidium, if you follow the manufacturer’s instructions correctly.

Iodine, tablets with iodine (tetraglycine hydroperiodide), or chlorine tablets kill most germs, but not Cryptosporidium. Water that has been disinfected with iodine is NOT recommended for pregnant women, people with thyroid problems, or those with known hypersensitivity to iodine.
It’s also not recommended for continuous use—don’t use it for more than a few weeks at a time.

Ultraviolet Light (UV Light)
Ultraviolet light (UV light) can be used to kill some germs.
Portable units that deliver a measured dose of UV light help disinfect small amounts of clear water. UV light does not work well on cloudy water because small particles may block germs from the light.
If the water is cloudy, first filter it through a clean cloth, paper towel, or coffee filter OR allow it to settle. Then, draw off the clear water and disinfect it using the UV light.
Always follow the manufacturer’s instructions.

Solar Disinfection
In emergencies, the sun’s rays can improve the quality of water. This method may reduce some germs in the water.
To disinfect water using the sun:
Fill clean and clear plastic bottles with clear water. Solar disinfection is not as effective on cloudy water because small particles may block germs from the light.
If the water is cloudy, first filter it through a clean cloth, paper towel, or coffee filter OR allow it to settle. Then, draw off the clear water and disinfect that water using the sun.
Lay the bottles down on their side and in the sun for 6 hours (if sunny) or 2 days (if cloudy). Laying down the bottles allows the sun’s rays to disinfect the water inside more effectively.
Putting the bottles on a dark surface will also help the sun’s rays disinfect the water more effectively.

Do you use BPA in or on the tanks?
Class A Customs does not carry this chemical nor uses it in the manufacturing process in any way.

Can the tank sit in the sun?
Yes, the tanks are UV-8 Stabilization, however this is not an algae or mold prevention. You will need to keep your tank clean and sanitized.

Will the tank material handle ___________ chemical?
Fresh/Gray Water Tanks & fittings made from DOW NSF International NSF/ANSI Std 61 approved Medium Density Polyethylene (MDPE) Resin and are to be used for Fresh or Gray Water only. We are not aware if the tanks can withstand placing other chemicals onto the tank such as spray foams, paints, adhesives. You would need to verify this information.

Can I pressurize your tanks?
No, all tanks Class A Customs manufactures must be vented (allow air in/out during use), Plumbing Example and Fill Dishes

Can I put boiling water into the tank?
No, boiling water is 212 °F (100 °C) Domestic hot - The temperature used during testing is 60 +/- 2°C (140 +/- 4 °F) and appears in Listings as "D. Hot". This is intended to apply to product applications where the product is used for either cold (ambient temperatures) or hot water up to domestic hot temperatures.

The tank smells like a candle?
Freshly made tanks may smell but it will disappear over time with exposure to air and water.

I need a clean-out hole for my tank.
We do not offer clean-out ports at this time but there are many options online that allow you to install the needed clean-out port.
You could install a Uniseal fitting into your tank and as long as you have a smooth sided deck mount this could be fitting into the Uniseal.

Can I have the fittings moved?
Can you add extra fittings to the tank?
Class A Customs no longer offers custom fittings unless you are ordering 50 or more of the same tanks per order.
We offer Uniseal fittings that allow the end user to place a fitting anywhere in the tank. Installation video and sizes.
Search Uniseal in top search bar or look in Plumbing Category.


1. Be sure to have recommended hole saw for selected fitting, check chart before cutting.
2. Using hole saw cut hole in wall, ensure that the hole is cut clean. Irregular holes could cause poor seating and possible leaks. File or sand the edges so there are no rough or sharp edges be sure to remove any remaining debris.
3. Insert the Uniseal with the wide surface facing out.
4. Make certain the pipe to be inserted is cut clean and square, file or sand the edges so there are no rough or sharp edges to cut the Uniseal surface.
5. Use liquid soap or Teflon lube on the pipe to be inserted. Insert the pipe into the Uniseal as far as needed to clear the inside of the seal by about 2".
6. Be sure to clean tank thoroughly prior to using removing any debris and lubricant residue

Search Uniseal in top search bar or look in Plumbing Category.

You will need to verify if items will fit your application, such as being food safe, we are not aware of this.

Dometic Universal Holding Tank Clean-out Kit

8 inch Boat Hatch Cover Deck Plate Hatch,White 8 inch Non Slip Inspection Hatch w/Detachable Cover

Someone accidentally put fuel into my water system, can I rinse it and just use it?
Class A Customs does not and can not recommend using a tank for fresh or drinking water after a contaminate such as fuel (gasoline, diesel or any other type of fuel) has been in the tank.

If someone has accidentally placed fuel into your fresh or drinking water supply it is highly recommended that you replace the entire system (water pumps, etc.), we understand this causes a financial strain to you and time down but the risk it simply too high to continue using the product after contamination. Replacing the entire system will ensure there are no possibilities of contamination from any areas that may have been exposed.

Can I use an old black water tank for fresh water if I clean it really good?
No, the health risks from using a previously used waste water tank for fresh or drinking water are extremely high and can not be recommended. Waste water tanks are also made from recycled materials and there is no guarantee if another material (paint / glue/ etc.) has been recycled along with the material, Waste Water Tanks are not for fresh or drinking water use.

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