Backyard pool in Tucson with the water lowered partway, a discharge hose running across the deck toward the house, desert landscaping and mountains

Tucson Pool Water Recycling and Draining: When, How and Where

Desert pool water slowly fills up with minerals until fresh water is the only fix. This guide covers when to dilute, drain or recycle, the City of Tucson and Pima County rules on discharge, and the risks of an empty pool in the heat.

Call (520) 372-1083 Jump to the local rules

Tucson pool water recycling and draining both answer the same problem: after a few seasons in the desert, the water in a pool can hold so many dissolved minerals that balancing it gets harder and scale keeps coming back. Fresh water is the cure. This guide explains why the water wears out, how to tell it is time, how a partial drain, a full drain and on-site recycling compare, and exactly where City of Tucson and Pima County rules let the old water go.

Tucson Pool Cleaning Pro does not drain or recycle pools. It is a free phone line that hands your call to an independent pool service company in the Tucson area. Its staff test the water, suggest a plan, run the pumps, quote their own price and collect payment from you.

Why pool water gets "old" in Tucson

Water leaves a pool in two ways. Some of it goes out through splash-out and filter backwashing, and that water carries its minerals with it. Most of it, in the desert, simply evaporates. Evaporation only removes pure water. The calcium, magnesium, salts and leftover chemical byproducts stay behind, and the water that remains gets a little more concentrated every day.

Then you top off. Tucson Water's supply is hard, the utility explains, because local groundwater is naturally hard and hardness climbs as the share of Central Arizona Project (CAP) water in the blend rises. Every refill brings in a fresh load of minerals. A pool trade article on hot, sunny climates makes the same point: losing water to the air and refilling with hard desert water steadily concentrates calcium, salts and other dissolved solids. The Arizona Department of Water Resources (ADWR) puts evaporation from open water in Tucson at about six feet a year, and says that for a typical pool, evaporation plus refills and backwashing comes to roughly a whole pool's worth of water each year.

Hand holding a pool water sample vial at the surface of a clear pool

Two terms come up when a pool company talks about old water. Total dissolved solids (TDS) means the sum of all the material carried in solution: minerals, salt and the residue of years of chemicals. Calcium hardness is the calcium part of that. A third, cyanuric acid, is the stabilizer that shields chlorine from sunlight. It is a useful tool under the Tucson sun, but it builds up when stabilized chlorine products are used, and the CDC notes that chlorine works more slowly when cyanuric acid is present. None of the three leaves the pool by evaporation. They only go down when water is replaced or filtered out.

Signs the water needs replacing

A water test, not the calendar, tells you when. A pool technician reads these results for clues.

High total dissolved solidsThe Pool and Hot Tub Alliance (PHTA) guidance is that TDS should rise no more than 1,500 ppm above the level the pool started with; beyond that, partial or full draining may be needed.
Calcium that keeps climbingScale returns quickly on the tile and equipment even after the water is balanced.
Too much stabilizerCyanuric acid readings are so elevated that the chlorine in the pool works sluggishly.
Hard to balance waterChemistry drifts and readings will not hold even with regular service.
Work that needs an empty shellReplastering, major tile work or some repairs cannot be done with water in the pool.

Partial drain, full drain or Tucson pool water recycling

There are three ways to get fresh water into a pool, and they trade water use, cost and risk against each other.

Partial drain and refill

Part of the water is pumped out and replaced. Replacing a third of the water dilutes what is dissolved in it by roughly a third, less whatever the new hard water brings in. The shell stays mostly covered, so the risks below are lower. It may not be enough when levels are very high.

Full drain and refill

All of the water goes and the pool starts over with fresh fill water. It is the only choice when the shell has to be empty for replastering or repairs. It uses the most water and leaves the finish and shell exposed, so timing and planning matter most here.

On-site water recycling

A mobile reverse osmosis unit filters the pool water and returns it, lowering TDS, calcium, salt and cyanuric acid without emptying the pool. Some concentrated waste water is still produced and must be disposed of, but it is a fraction of a full drain.

How mobile pool water recycling works

Reverse osmosis (RO) pushes water through membranes fine enough to hold back dissolved minerals and salts. For pools, the equipment is usually built onto a truck. Hoses run from the pool to the unit, the water is pumped through the membranes and the filtered water goes straight back into the pool, which usually stays full while the job runs. Trade coverage describes it as a way to lower TDS, calcium, salt and stabilizer without a drain. The leftover concentrate, which holds the minerals that were removed, still has to be disposed of properly, so ask where it will go. One residential case study in AQUA Magazine, written by the company that did the job, reported keeping about 19,500 gallons of a roughly 24,000 gallon pool compared with draining and refilling it.

Not every pool company owns this equipment. When the line connects you, find out whether that company offers recycling or can arrange it, how much water it expects to recover for your pool, and where the concentrate will be discharged. Recycling also skips one problem with draining: the refill water in Tucson is hard to begin with, so a fresh fill restarts the mineral cycle from a fairly high base.

Tucson and Pima County rules on draining pool water

The City of Tucson and Pima County's Regional Wastewater Reclamation Department publish shared guidelines for pool and spa water. In plain terms, they say:

Allowed and preferred

Discharge to the sanitary sewer through the access cap of your own property's sewer cleanout, using a hose and a small pump.
Pump during low-use sewer hours and control the flow so the cleanout never overflows.
Leave the water untreated for at least 72 hours after the last chlorine, then measure the pH and adjust it to 7 to 8.
Filter backwash may go on your own land only if it soaks into the ground within 24 hours and never reaches a neighbor's property, the street or an alley.

Not allowed

Using public manholes or public cleanouts.
Running water down the curb, into storm drains or into washes when a private cleanout exists. That route is a last resort only, and only for clear, dechlorinated water in the 7 to 8 pH range that causes no erosion and stays off neighbors' property and sidewalks.
Letting acid wash water run off into the curb, storm drains or washes.
Letting backwash flow off your property.
Connecting a pool permanently to a storm drain or wash.

The city notes that backwash water often carries chlorine, germs and other contaminants that should stay on site, and its inspectors do respond to reports of pool water in the street. If you have questions, the city's Stormwater Management Section is at (520) 791-4251, and Pima County's wastewater department is at (520) 724-6500. If you live in Oro Valley, Marana, Sahuarita or another town, also check that town's rules before anyone pumps.

A drain, step by step

This table shows how a careful drain usually runs and who handles each part. Use it to plan and to ask good questions. The pumping, any acid work and the restart belong with the pool company.

Steps in draining a pool in Tucson, what happens, why it matters and who handles it
Step	What happens	Why it matters	Who
1. Test and decide	The water is tested for TDS, calcium and stabilizer, and you choose partial drain, full drain or recycling.	The right amount of fresh water depends on the numbers.	Pool company, with you
2. Check the shell and timing	The type of pool, the finish, the hydrostatic relief valve and the forecast are reviewed.	An empty shell can be damaged by heat or by water pressure in the ground.	Pool company
3. Stop the chlorine	No chlorine goes in for at least 72 hours.	Required before discharge under city and county guidelines.	You and the pool company
4. Check the pH	The pH is measured and brought to 7 to 8.	Required before any water is released.	Pool company
5. Pump to the cleanout	Water goes through your private sewer cleanout at low-use hours, flow controlled.	The sewer is the preferred, legal route.	Pool company
6. Work while empty	Cleaning, tile work, repairs or replastering are done as quickly as possible.	The longer the finish is dry, the higher the risk.	Pool company or other contractor
7. Refill and restart	The pool is filled, equipment is restarted and the new water is balanced.	Fresh Tucson water still needs balancing to protect the finish.	Pool company

Wondering whether your pool needs a partial drain, a full drain or recycling? Call any hour. The independent pool company you reach can test the water and walk you through its plan and price.

Call (520) 372-1083

The risks of an empty pool in the Tucson heat

The finish dries out

The National Plasterers Council explains that cement based pool finishes are meant to stay underwater. Exposure to air starts drying them, hot, dry or windy weather speeds that up, and long exposure can damage the finish. The council ranks weather as the leading factor in when and how long a pool can stay empty, and says rescheduling is the best choice when extreme weather is expected. Tucson's normal July high is about 100 degrees, so a midsummer drain asks a lot of the plaster.

The shell can be pushed up

A full pool is held down by the weight of its water. Empty, it can be lifted by water pressure in the ground around it. Pool trade sources describe empty pools floating up out of the ground when water pressure builds beneath them, in one reported case tilted at a steep angle after the relief valve jammed. Their advice before draining is to know the local water table and make sure the pool's hydrostatic relief valve works. This is a key reason the decision belongs with a pool professional.

Who to call and what to ask

Pool pump and plumbing beside a tall filter tank against a sunlit stucco wall

A pool service company is the right call for any drain or recycling job. It can test the water, judge the shell and finish, handle the pump and hoses, keep the discharge legal and restart the pool. Leave acid washing and any chemical work to the professional. The CDC is clear that pool chemicals must never be mixed with each other, and acid wash water has its own discharge limits.

While the pool is low, it is a good time to deal with scale on the tile; see pool tile cleaning in Tucson. If you are draining to find or fix a leak, read pool leak repair first, and for a pool that has turned green, start with my pool is green: what do I do.

What do the TDS, calcium hardness and cyanuric acid readings show, and what is the goal after?
Partial drain, full drain or recycling: which do you recommend for my pool, and why?
Do you offer mobile water recycling, and where does its concentrate go?
Is there a working hydrostatic relief valve, and what keeps the shell in place?
How long will the pool be empty, and how will you protect the finish in this weather?
Will you use my private sewer cleanout, and how will you control the flow?
Is refilling and balancing the new water part of the price?
What is your Arizona ROC license number? You can check it on the Registrar of Contractors search.

For routine care between drains, see pool cleaning and weekly maintenance and the Tucson pool maintenance schedule.

How the free line works

Dial the line(520) 372-1083 is picked up by an automated assistant around the clock, holidays included.
Say what the pool is doingGreen water, a pump that is silent or grinding, a light that will not come on, white crust on the tile, plus the part of the Tucson area you live in.
Get transferredYour call is handed to a pool service company in the Tucson area that is independent and locally owned. It gets a quick summary of the problem before it says hello.
Work it out with themThat company inspects, quotes, does the job and bills you itself. If nobody picks up, your name, number, area and pool problem go to the company so it can phone you back.

About this line: Tucson Pool Cleaning Pro is a free phone line, not a pool company. It answers your call and connects you with an independent local pool service company, which inspects, quotes and does the work, and which you pay directly. Companies may pay a referral fee. The line never charges you. Read how the line works.

Related pool help

Areas the line covers

Common questions

Is it legal to drain pool water into a Tucson street?

Usually not. The City of Tucson and Pima County treat the home's own sewer cleanout as the preferred route. Curbside, storm drain or wash discharge is a last resort, allowed only when there is no access to a private cleanout and the water has gone at least 72 hours without chlorine, has a pH between 7 and 8, is clear, has not been used for an acid wash and will not flow onto neighbors' property or sidewalks or cause erosion.

What is pool water recycling?

It is on-site filtering of the water already in your pool, usually by a truck mounted reverse osmosis unit. Pool water is pumped through very fine membranes that hold back dissolved minerals, salts and stabilizer, and the cleaned water goes back into the pool. A smaller amount of concentrated waste water is left over and still has to be disposed of properly, but much less water leaves than in a full drain and refill.

How long after adding chlorine can I drain my pool?

Tucson and Pima County discharge guidelines say to leave the water untreated for at least 72 hours (three days) after the last chlorine was added, then measure the pH and bring it into the 7 to 8 range before any water is released.

How many years can Tucson pool water go before draining?

There is no set number of years. A pool needs fresh water when testing shows dissolved solids, calcium or stabilizer have climbed too high. The Pool and Hot Tub Alliance treats a total dissolved solids reading more than 1,500 ppm above the level at startup as a sign that partial or full draining may be needed. Hard fill water and heavy evaporation make Tucson pools reach that point faster than pools in rainier places.

Is it bad to drain a pool in the summer in Tucson?

It carries more risk. The National Plasterers Council says pool finishes are meant to stay wet, that hot, dry or windy weather speeds up drying of an exposed finish, and that weather is the top factor in deciding when and how long a pool can sit empty. Tucson averages about 68 days a year at 100 degrees or more, so a cooler, calmer stretch is usually a safer window. Ask your pool company before you plan a summer drain.

Water worn out? Talk it through with a local pool company

It is one free call, day or night. Tell the assistant what the pool is doing and which part of the Tucson area it is in, and you are transferred to a local, independently owned pool company that looks at the pool in person and names its own price.

Call (520) 372-1083

Around the clockNights, weekends and holidays, every call gets an automated answer.
Free to callThe line never sends you a bill. Prices come only from the pool company.
Check the ROC numberBefore any repair or equipment job, get the company's state contractor number and search it on the ROC website.
Your call to makeListen to what the company found and what it will cost, then decide whether to hire it.