What if your roof could water your garden and protect local beaches at the same time? In Mar Vista, a few well-placed rain barrels or a compact cistern can turn seasonal storms into a practical resource for your landscape. You care about curb appeal and coastal living, and you want your home to perform beautifully too. In this guide, you’ll learn how much water you can realistically capture, how to size and install a system that fits your space, when to get it done, and where to look for local giveaways or incentives. Let’s dive in.
Why capture rain in Mar Vista
Mar Vista sits on Los Angeles’ Westside where rooftops, driveways, and streets send stormwater quickly toward Ballona Creek and the ocean. Capturing rain on-site helps reduce runoff and local flooding while cutting the pollution that reaches our beaches. It also gives you a free source of irrigation water for gardens and trees. If you route overflow to planted or permeable areas, you support tree health and help water soak into the ground on your property.
How much water your roof can provide
Coastal Los Angeles averages about 15 inches of rain per year, mostly from October through April with peaks from December to March. That means you can collect useful volumes for irrigation across the season.
Use this simple formula to estimate your capture potential per storm:
- Gallons collected = Roof area (sq ft) × Rainfall (inches) × 0.623 × Runoff coefficient
- Typical runoff coefficients:
- Smooth metal or tile roof: 0.9
- Asphalt shingle roof: 0.8
Example: A 1,000 sq ft roof in a 1 inch storm with an asphalt shingle coefficient of 0.8 can yield roughly 1,000 × 1 × 0.623 × 0.8, which is about 500 gallons.
Over a full season, the total potential adds up, but you will only capture what your storage can hold between storms. That is why right-sizing storage is key.
Choose the right storage
- Rain barrels (50 to 100 gallons): Affordable, easy to install, and perfect for container gardens, shrubs, and trees. You can place more than one and connect them in series.
- Small cisterns (200 to 2,000+ gallons): Better for larger landscapes or when you want to store multiple storms’ worth of water. These can be above ground or underground.
- Underground options: Useful if you need capacity without a visual footprint, but they cost more and often require permits and skilled installation.
Size your system in three steps
Measure the roof area feeding your downspout. If only part of the roof drains to the chosen downspout, estimate that area. Even 300 to 500 sq ft can be worthwhile.
Estimate capture using the formula. Start with a 1 inch storm to see single-event volume, then consider a seasonal estimate if you want to plan for multiple reuses.
Match storage to how you will use water between storms. In Mar Vista, many homeowners target 100 to 500 gallons for garden use. If you want to store most of a single larger storm, you would need several hundred to a few thousand gallons, depending on roof size. For most homes, capturing the first portion of each storm is the most cost-effective approach.
Quick examples:
- 500 sq ft roof, 1 inch storm, asphalt shingles: about 500 × 1 × 0.623 × 0.8, or roughly 250 gallons. Two to three standard barrels can catch a big portion of that first flush.
- 1,200 sq ft roof, full season of 15 inches, asphalt shingles: about 1,200 × 15 × 0.623 × 0.8, or roughly 9,000 gallons over the season. You will only capture what your system can store and you choose to use before the next storm.
Install with confidence
Pick the location
Place barrels or a cistern under a downspout that drains a meaningful roof area. Set the barrel on a solid, level base such as a concrete pad or stacked concrete blocks. Raising the barrel gives you gravity pressure for the spigot and makes it easier to fill watering cans. Remember that 1 gallon weighs about 8.34 pounds, so a full 100 gallon barrel weighs about 834 pounds. Make sure the stand can safely support the load.
Connect the gutter and downspout
Use a downspout diverter or adapter that sends water into the barrel and automatically bypasses back into the downspout when the barrel is full. Add a removable leaf screen at the inlet to keep debris out. Direct any overflow to a permeable area, rain garden, or other approved location. Do not discharge onto a neighbor’s property.
Add a first-flush diverter
A first-flush diverter helps improve water quality by capturing the initial roof runoff that typically contains more dust and debris. Small residential diverters often capture 5 to 20 gallons before sending cleaner water into your storage. You can buy a commercial unit or assemble a simple DIY version with a short pipe and valve that you drain after storms.
Control mosquitoes and water quality
Keep all inlets, overflows, and vents covered with fine mesh, and keep lids sealed. For standing water used for irrigation, consider EPA-registered mosquito larvicides such as BTI products and follow the label. Plan to use captured water for non-potable purposes like irrigation, car washing, and outdoor cleaning.
Plan safe overflow and infiltration
During heavy storms, your barrel may fill quickly. Route overflow into planted areas, a drywell, or an infiltration trench where water can soak into the soil. If you must discharge toward the street or sidewalk, confirm local stormwater rules for allowable locations before you do.
Decide on gravity or a pump
A raised barrel usually provides enough gravity flow for hand watering and simple drip lines. If you need pressurized irrigation, you will likely need a pump and a pressure regulator. Any connection to indoor plumbing requires proper backflow prevention and may need permits.
Seasonal timing and care
When to install
Aim to have your system in place by October or November so you can catch early-season storms. Installations completed in late summer or early fall allow time to clean gutters, test connections, and fine-tune overflow routing.
Routine maintenance
- Before the rainy season: Clean gutters and downspout screens, check diverters, and confirm the barrel stand is secure.
- During the season: Inspect monthly for debris, clean screens, and confirm seals and overflow are working as designed.
- Twice per year: Check for algae and sediment. Flush the bottom of the barrel if needed.
- Winter notes: Freezing is uncommon in Los Angeles. Draining or disconnecting for freeze protection is usually not required.
- Summer: Use stored water for landscape irrigation. Treat for mosquitoes if you notice standing water and always keep screens intact.
Safety notes
Label outlets as non-potable and never connect untreated rainwater to your drinking water. If you want to explore indoor non-potable uses like toilet flushing or laundry, consult local codes and install any required treatment and backflow protection.
Local programs and where to look
Public agencies and water districts update programs regularly, and availability changes throughout the year. Check these sources for giveaways, workshops, and rebates:
- Los Angeles Sanitation & Environment (LASAN) Stormwater Program for outreach, community rain barrel events, and stormwater capture initiatives.
- Los Angeles Department of Building and Safety (LADBS) for permit guidance on large cisterns, buried tanks, and any plumbing changes.
- Los Angeles Department of Water & Power (LADWP) for conservation programs that may include rain barrel promotions, as well as turf removal and smart controller rebates.
- West Basin Municipal Water District, Metropolitan Water District, and other local water agencies for co-sponsored workshops or incentives, depending on your service area.
- Los Angeles County Department of Public Works watershed programs and local watershed groups in the Ballona Creek basin for education and neighborhood events.
- Mar Vista Community Council, MyLA311, local nurseries, community gardens, and environmental non-profits for event announcements and workshops.
Tip: Call or check the agency websites in early fall when programs and event calendars are often refreshed ahead of the rainy season.
Quick specs checklist
Use this list to streamline your installation:
- Storage: 50 to 100 gallon barrels, or 200 to 2,000+ gallon cisterns based on your goals.
- Base: Level, load-bearing platform of concrete blocks or a small pad.
- Downspout diverter: Automatic bypass when full, with a cleanable leaf screen.
- First-flush diverter: 5 to 20 gallon capacity for small residential roofs.
- Screens and lids: Fine mesh on all openings and a tight-fitting lid to block mosquitoes and debris.
- Overflow: Directed to a permeable area, rain garden, drywell, or approved outlet.
- Labeling: Mark outlets as non-potable.
- Optional pump: Add only if you need pressurized irrigation.
Bring it all together
A well-sized, well-installed rain barrel system turns the rhythm of Mar Vista’s rainy season into a reliable, on-site resource. You cut runoff to Ballona Creek, support a healthier landscape, and free yourself to water trees and beds even during dry spells. Start with one or two barrels near your most useful downspout, then expand if you find you use everything you collect. With a weekend of planning and a few smart components, your home can look great and perform beautifully through the season.
Ready to match smart sustainability with style at home or across your next move on the Westside? Connect for local guidance and design-forward real estate advice. [Unknown Company] has the neighborhood perspective and trusted referrals to help you plan upgrades that fit your property vision. Start Your Journey Here.
FAQs
How much roof area do I need for a rain barrel in Mar Vista?
- Even small roofs are useful. A single 50 to 100 gallon barrel is often worth installing for container gardens and trees.
Do I need a permit for a 55 to 100 gallon barrel in Los Angeles?
- Usually not, but verify with the Los Angeles Department of Building and Safety and Los Angeles Sanitation & Environment, especially for larger tanks or plumbing changes.
When should I install rain barrels in Mar Vista?
- Install by October or November so you are ready for the main rainy season from October through April.
How do I calculate how much my roof can collect?
- Multiply roof area by rainfall in inches by 0.623 and then by a runoff coefficient such as 0.8 for asphalt shingles.
How do I keep mosquitoes out of rain barrels?
- Use fine mesh screens on all openings, keep lids sealed, and consider EPA-registered BTI products according to label directions.
Is rainwater safe for my plants and trees?
- Yes. Rainwater is typically preferred for irrigation. Do not use untreated rainwater for drinking.
Where can I find rain barrel giveaways or rebates in Los Angeles?
- Check LASAN’s stormwater outreach, LADWP conservation pages, local water districts, the Mar Vista Community Council, and MyLA311 for events and updates.
