ST. GEORGE — Keeping the grass green in the sizzling heat of the Mojave Desert is no easy feat, and reports of low water pressure coming from St. George residents’ sprinklers aren’t helping the matter.
Officials from St. George Water Services say the low pressure is the result of a massive load on the city’s water system during what appears to be everyone’s favorite watering hours, 4-6 a.m.
During the summer months, the city provides over 40 million gallons of water per day to its customers. Over a quarter of those 40 million gallons is delivered in just that two-hour window, greatly reducing the water pressure available to some homes.
The large drop in pressure lowers the efficiency of sprinkler systems, possibly decreasing sprinkler coverage area and resulting in dry spots on lawns that can’t be mitigated by simply running sprinklers longer.
“Our water distribution system is so complex, so dynamic – it changes constantly – there’s going to be a lot of residents that may not notice a drop in pressure,” Water Services Director Scott Taylor told St. George News.
Water pressure is related to elevation, so those who live on a hill close to a tank won’t have as high pressure as someone in downtown St. George. Even if a homeowner doesn’t notice a drop in pressure during the peak watering times, other people at higher elevations likely will.
The lower pressure may also not be as noticeable indoors because most homes are equipped with pressure-reducing valves that limit indoor water pressure.
“In an effort to improve water pressure citywide, we are asking residents to adjust their sprinkler clocks to avoid watering between the hours of 4 a.m. and 6 a.m.,” Taylor said.
Spreading out water times will make overall water delivery more even throughout the day, he said.
Ideally, people can also contribute to evening out water pressure by setting sprinkler systems to water over four 15-minute increments spread out over a period of two hours.
Evening out watering times is especially essential during the hot summer months, Taylor said, noting that watering peaks between July 4 and July 24.
Low humidity during the summer months also means lawns watered in the early morning hours aren’t susceptible to fungal growth because any lingering water evaporates quickly, Parks Manager Shane Moore explained during a recent public meeting.
Watering times should also not be set between 8 a.m. and 8 p.m. Daytime watering during those hours is currently banned by an ordinance instituted by the City Council in May.
Read more: St. George enacts daytime watering ban
Taylor said the city has plenty of water to go around, with lots of sources available, such as from Sand Hollow and Quail Creek reservoirs.
“It’s not an issue of not having enough water,” he said. “We’ve got plenty water, and we can deliver it to the customers. The only issue is that two-hour period in the morning, our pressure in the system drops, and it’s more if an inconvenience than anything.”
“This isn’t a problem that’s unique to St. George,” he said, noting that he recently met with officials from surrounding cities who were experiencing similar issues. “Every community faces the same thing.”
And expensive infrastructure upgrades aren’t necessarily a solution.
“If you have oversized infrastructure, during the winter when there’s not a lot of demand, that water sits there longer and then you have a water quality issue with stagnating water,” Taylor said.
“It’s kind of a balancing act,” he said. “You want the infrastructure big enough to be able to provide the water that’s needed, but yet if you get too big, it’s a whole other issue that we have to deal with. I think we’re properly sized.”
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