Calculate Hot Tub Refill Cost:
When in doubt, drain it out!
San Diego County Water Authority
Unless you own a well, you get your water from one of the 24 agencies that make up the San Diego County Water Authority.
Water rates are divided into tiers based on the amount of water you use. If you use a lot of water you pay a little more. If you conserve water you pay a little less.
Water rates vary between districts but the highest standard water rate you can pay in the City of San Diego is $11.13 per "unit" of water (February 2019).
A "unit" is 100 Cubic Feet (HCF) or 748 gallons
City of San Diego Water Rates (February 2019):
- 0 - 4 HCF = $4.946 per 748 gallons = $0.0066 per gallon
- 5 - 12 HCF = $5.540 per 748 gallons = $0.0074 per gallon
- 13 - 18 HCF = $7.915 per 748 gallons = $0.0105 per gallon
- Over 18 HCF = $11.130 per 748 gallons = $0.0148 per gallon
A typical single-family home in the City of San Diego uses 83,000 gallons per year or 9.5 HCF per month so most people pay $5.540 for 748 gallons of water.
$5.540/HCF ÷ 748 gallons = $0.0074 per gallon!
Simple Hot Tub Chemistry starts with the idea that the fresh water coming out the end of your garden hose only costs $0.0074 or 7/10 of one penny per gallon.
That means you can replace 400 gallons of water for less money than driving to the store and buying a single quart or even a single pint of any specialty product sold to treat 'complex' water problems.
Portable hot tubs come in all shapes and sizes from 200 gallon plug-in models you can push onto your patio to 2,000 gallon swim-spas that can only be delivered with a crew and a crane but a good average for a typical hot tub is around 400 gallons.
400 gallons × $0.0074 per gallon = $2.96
$2.96 to refill a 400 gallon hot tub!
Even when you add in sewer rates you can still refill the average 400 gallon hot tub for less than the cost of a single pint of any product designed to treat the water!
|Cost per Gallon
|Cost per Gallon
Portable hot tub owners pour pounds of chemistry and buckes of money into a a batch of water because the instructions on the bottle tell them to. Don't get burned soaking in a caustic, chemical brew!
Just because you can fix a problem by adding more chemistry doesn't mean you should. Would you rather spend $50.00 at the supply store so you can soak in more chemical byproducts or spend $2.96 at the end of your garden hose so you can soak in a clean, fresh batch of water?
But what about wasting water?
Your portable hot tub doesn't actually use water. Your covered, insulated tub is essentially a sealed tank that stores and recycles water. In fact, (unless you own a fish tank) your hot tub is the most water-efficient appliance in your home!
Every other water-using appliance in your home uses water because it dumps every drop of water down the drain after just one use. High-efficiency clothes washers dump 15 to 30 gallons per load. Older washers dump 29 to 40 gallons per load!
Your portable hot tub is the only appliance that stores 400 gallons then automatically filters and recycles every gallon every day so you can soak in the same batch of water for weeks or months!
You get more miles-per-gallon from your portable hot tub than any other applliance in your home so you should never feel guilty about draining your hot tub and refilling it with a fresh, clean batch of water.
Visit the Simple Hot Tub Chemistry Explained page for a more tips on water conservation for hot tub owners.