How to Keep a Water Tank at the Same Level

The easiest way to keep a water tank at a constant level is to install a simple float valve or ballcock. This can be done in any kind of tank, from an aquarium to a toilet to a stock pond. The float rides on top of the water, and when the level drops too far, the lever of the ballcock activates a valve to shut off incoming water until the float comes back to the predetermined level. Float-valve kits are sold at most hardware, plumbing supply and home improvement stores.

Things You'll Need

  • Float valve/ballcock kit
  • Drill with appropriate bit
  • Teflon tape
  • Hand tools, such as a wrench and pliers
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Instructions

    • 1

      Turn off the water at the source.

    • 2

      Select and mark the desired water level in the tank. Lower the water level in the tank as necessary before you drill through the tank wall. If you can't drill a hole because your tank is glass, consult an aquarist for alternatives.

    • 3

      Drill an appropriate-size hole in the tank wall about one inch above the marked water level for an inlet.

    • 4

      Assemble all parts according to the kit instructions.

    • 5

      Seat the inlet fitting in the inlet. Screw the mounting snugly against the outside of the tank wall.

    • 6

      Attach the tubing and connector to the inlet fitting and tighten.

    • 7

      Place the float valve in the tank and attach it at the inlet. Make sure it floats freely and does not interfere with any other equipment.

    • 8

      Turn on the water and check for leaks.

    • 9

      Watch the float valve as the tank fills until the water reaches the marked level to be sure it shuts off the incoming water correctly. If it does not, shut off the water at the source, adjust the valve and test again.